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| ? 2010 microchip technology inc. ds21996d-page 1 mcp98242 features: ? temperature sensor + 256 byte serial eeprom ? eeprom for serial presence detect (spd) ? optimized for voltage range: 3.0v to 3.6v ? shutdown/standby current: 3 a (maximum) ? 2-wire interface: i 2 c?/smbus compatible ? available packages: dfn-8, tdfn-8, udfn-8, tssop-8 temperature sensor features: ? temperature-to-digital converter ? operating current: 200 a (typical) ?accuracy: - 0.5c/1c (typ./max.) ? +75c to +95c - 1c/2c (typ./max.) ? +40c to +125c - 2c/3c (typ./max.) ? -20c to +125c serial eeprom features: ? operating current: -write ?? 1.1 ma (typical) for 3.5 ms (typical) - read ?? 100 a (typical) ? permanent and reversible software write-protect ? software write protection for the lower 128 bytes ? organized as 1 block of 256 bytes (256x8) typical applications: ? dimm modules ? laptops, personal computers and servers ? hard disk drives and other pc peripherals description: microchip technology inc.?s mcp98242 digital temperature sensor converts temperature from -40c and +125c to a digital word. this sensor meets jedec specification jc42.4 mobile platform memory module thermal sensor component. it provides an accuracy of 0.5c/1c (typical/maximum) from +75c to +95c. in addition, this device has an internal 256 byte eeprom which can be used to store memory module and vendor information. the mcp98242 digital temperature sensor comes with user-programmable registers that provide flexibility for dimm temperature-sensing applications. the registers allow user-selectable settings such as shutdown or low-power modes and the specification of temperature event and critical output boundaries. when the temperature changes beyond the specified boundary limits, the mcp98242 outputs an event signal. the user has the option of setting the event output signal polarity as either an active-low or active-high comparator output for thermostat operation, or as a temperature event interrupt output for microprocessor-based systems. the event output can also be configured as a critical temperature output. the eeprom is designed specifically for dram dimms (dual in-line memory modules) serial presence detect (spd). the lower 128 bytes (address 00h to 7fh) can be permanent write-protected (pwp) or software reversible write-protected (swp). this allows dram vendor and product information to be stored and write-protected. the upper 128 bytes (address 80h to ffh) can be used for general purpose data storage. these addresses are not write-protected. this sensor has an industry standard 2-wire, i 2 c/ smbus compatible serial interface, allowing up to eight devices to be controlled in a single serial bus. to maintain interchangeability with the i 2 c/smbus interface the electrical specifications are specified with the operating voltage of 3.0v to 3.6v. in addition, a 40 ms (typical) time out is implemented. package types memory dimm module temperature sensor + eeprom mcp98242 3.3v dd _ spd sda scl ? 0.5c (typ.) sensor ? 256 byte eeprom for spd event 8-pin dfn/tdfn/udfn (2x3) * sda gnd event sclk mcp98242 1 2 3 4 8-pin tssop a0 v dd a1 a2 8 7 6 5 a2 a1 gnd event sclk 1 2 3 4 8 7 6 5 sda v dd a0 ep 9 * includes exposed thermal pad (ep); see ta b l e 3 - 1 . memory module temperature sensor w/eeprom for spd
mcp98242 ds21996d-page 2 ? 2010 microchip technology inc. notes: ? 2010 microchip technology inc. ds21996d-page 3 mcp98242 1.0 electrical characteristics absolute maximum ratings ? v dd .................................................................................. 6.0v voltage at all input/output pins ............... gnd ? 0.3v to 6.0v pin a0 ................................................... gnd ? 0.3v to 12.5v storage temperature .....................................-65c to +150c ambient temp. with power applied ................-40c to +125c junction temperature (t j ) .......................................... +150c esd protection on all pins (hbm:mm) ................. (4 kv:300v) latch-up current at each pin (+25c) ..................... 200 ma ?notice: stresses above those listed under ?maximum ratings? may cause permanent damage to the device. this is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this s pecification is not implied. exposure to maximum rating conditions for extended periods may affect device reliability. dc characteristics electrical specifications: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground, sda/scl pulled-up to v dd , and t a = -20c to +125c. parameters sym min typ max unit conditions power supply operating voltage v dd 3.0 ? 3.6 v operating current temperature sensor i dd ? 200 500 a eeprom inactive eeprom write i dd ? 1100 2000 a sensor in shutdown mode (for t wc ) eeprom read i dd ? 100 500 a sensor in shutdown mode shutdown current i shdn ? 1 3 a eeprom inactive, sensor in shutdown mode power-on-reset (por) threshold v por ? 2.3 ? v temperature sensor (v dd falling) v por ? 1.6 ? v eeprom (v dd falling) (see section 5.4 ?summary of temperature sensor power-on default? ) power supply rejection, t a = +25c ? c/ ? v dd ?0.4?c/vv dd = 3.0v to 3.6v ? c/ ? v dd ?0.15? cv dd = 3.3v+150 mv pp ac (0 to 1 mhz) temperature sensor accuracy +75c < t a ? +95c t acy -1.0 0.5 +1.0 c +40c < t a ? +125c t acy -2.0 1 +2.0 c -20c < t a ? +125c t acy -3.0 2 +3.0 c t a ?? -40c t acy ?-2?c conversion time 0.25c/bit t conv ? 65 125 ms 15 s/sec (typical) (see section 5.2.3.3 ?temperature resolution? ) event output (open-drain) high-level current (leakage) i oh ?? 1 av oh = v dd low-level voltage v ol ??0.4vi ol = 3 ma eeprom write cycle (byte/page) t wc ?3 5ms? endurance t a = +25c ? 1m ? ? cycles v dd = 5v, note 1 write-protect high voltage v hi_wp 8 ? 12 v applied at a0 pin, note 1 thermal response note 1: characterized but not production tested. mcp98242 ds21996d-page 4 ? 2010 microchip technology inc. graphical symbol description dfn t res ? 0.7 ? s time to 63% (89c) 25c (air) to 125c (oil bath) tssop t res ?1.4? s dc characteristics electrical specifications: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground, sda/scl pulled-up to v dd , and t a = -20c to +125c. parameters sym min typ max unit conditions note 1: characterized but not production tested. input/output pin dc characteristics electrical specifications: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground and t a = -20c to +125c. parameters sym min typ max units conditions serial input/output (scl, sda, a0, a1, a2) input high-level voltage v ih 2.1 ? ? v low-level voltage v il ??0.8v input current i in ??5a output (sda) low-level voltage v ol ??0.4vi ol = 3 ma high-level current (leakage) i oh ??1av oh = v dd low-level current i ol 6??mav ol = 0.6v capacitance c in ?5?pf sda and scl inputs hysteresis v hyst ?0.5?v note: the serial inputs do not load the serial bus for v dd range of 1.8v to 5.5v. v dd v ih v il i in voltage current time v dd i oh voltage current time input output v ol i ol temperature characteristics electrical specifications: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground. parameters sym min typ max units conditions temperature ranges specified temperature range t a -20 ? +125 c ( note 1 ) operating temperature range t a -40 ? +125 c storage temperature range t a -65 ? +150 c thermal package resistances note 1: operation in this range must not cause t j to exceed maximum junction temperature (+150c). ? 2010 microchip technology inc. ds21996d-page 5 mcp98242 0 timing diagram thermal resistance, 8l-dfn ? ja ? 84.5 ? c/w thermal resistance, 8l-tdfn ? ja ?41?c/w thermal resistance, 8l-tssop ? ja ?139? c/w temperature characteristics electrical specifications: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground. parameters sym min typ max units conditions note 1: operation in this range must not cause t j to exceed maximum junction temperature (+150c). sensor and eeprom serial interface timing specifications electrical specifications: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground, t a = -20c to +125c, c l = 80 pf, and all limits measured to 50% point. parameters sym min typ max units conditions 2-wire i 2 c?/smbus-compatible interface serial port frequency f sc 10 ? 100 khz i 2 c?/smbus low clock t low 4.7 ? ? s high clock t high 4.0 ? ? s rise time t r ? ? 1000 ns (v il max - 0.15v) to (v ih min + 0.15v) fall time t f ? ? 300 ns (v ih min + 0.15v) to (v il max - 0.15v) data setup before sclk high t su-data 250 ? ? ns data hold after sclk low t h-data 300 ? ? ns start condition setup time t su-start 4.7 ? ? s start condition hold time t h-start 4.0 ? ? s stop condition setup time t su-stop 4.0 ? ? s bus idle t b_free 4.7 ? ? s time out t out 25 40 50 ms temp. sensor only (characterized but not production tested) t su -start t h - s t a r t t su - data t su - s top t b- f ree sc l k sda t h-data t h i g h t l ow t out t r , t f start condition data transmission stop condition mcp98242 ds21996d-page 6 ? 2010 microchip technology inc. notes: ? 2010 microchip technology inc. ds21996d-page 7 mcp98242 2.0 typical performance curves note: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground, sda/scl pulled-up to v dd , and t a = -20c to +125c. figure 2-1: average temperature accuracy. figure 2-2: temperature accuracy histogram, t a = +95c. figure 2-3: temperature accuracy histogram, t a = +75c. figure 2-4: supply current vs. temperature. figure 2-5: shutdown current vs. temperature. figure 2-6: power-on reset threshold voltage vs. temperature. note: the graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. the performance characteristics listed herein are not tested or guaranteed. in some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 -40-20 0 20406080100120 t a (c) temperature accuracy (c) v dd = 3.0v to 3.6v spec. limits 0% 10% 20% 30% 40% 50% 60% 70% -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 temperature accuracy (c) occurrences t a = +95c v dd = 3.3v 221 units 0% 10% 20% 30% 40% 50% 60% 70% -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 temperature accuracy (c) occurrences t a = +75c v dd = 3.3v 221 units 1 10 100 1000 10000 -40 -20 0 20 40 60 80 100 120 t a (c) i dd (a) v dd = 3.3v to 3.6v eeprom write (sensor in shutdown mode) sensor (eeprom inactive) eeprom read (sensor in shutdown mode) 0.00 0.50 1.00 1.50 2.00 2.50 3.00 -40 -20 0 20 40 60 80 100 120 t a (c ) i shdn (a) v dd = 3.0v to 3.6v 0 0.5 1 1.5 2 2.5 3 -40 -20 0 20 40 60 80 100 120 t a (c) v por (v) mcp98242 ds21996d-page 8 ? 2010 microchip technology inc. note: unless otherwise indicated, v dd = 3.0v to 3.6v, gnd = ground, sda/scl pulled-up to v dd , and t a = -20c to +125c. figure 2-7: event and sda v ol vs. temperature. figure 2-8: conversion rate vs. temperature. figure 2-9: power supply rejection vs. frequency. figure 2-10: sda iol vs. temperature. figure 2-11: temperature accuracy vs. v dd . figure 2-12: package thermal response. 0 0.1 0.2 0.3 0.4 -40-20 0 20406080100120 t a (c) event & sda v ol (v) event sda v dd = 3.0v to 3.6v i ol = 3 ma 35 50 65 80 95 110 125 -40-20 0 20406080100120 t a (c) t conv (ms) v dd = 3.0v to 3.6v -1.0 -0.5 0.0 0.5 1.0 100 1,000 10,000 100,000 1,000,000 frequency (hz) normalized temp. error (c) c/ v dd , v dd = 3.3v + 150 mv pp (ac) 1k 10k 100k 1m 100k 1m 10k 100k 1m 1k 10k 100k 1m 100 1k 10k 100k 1m t a = +25c no decoupling capacitor 6 12 18 24 30 36 42 48 -40 -20 0 20 40 60 80 100 120 t a (c) sda i ol (ma) v dd = 3.0v to 3.6v v ol = 0.6v -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 -40-20 0 20406080100120 t a (c) temperature accuracy (c) v dd = 3.0v v dd = 3.6v c/ v dd = 0.4c/v 0% 20% 40% 60% 80% 100% 120% -2 0 2 4 6 8 10 12 14 16 time (s) thermal response (%) 22c (air) to 125c (oil bath) tssop-8 dfn-8 ? 2010 microchip technology inc. ds21996d-page 9 mcp98242 3.0 pin description the descriptions of the pins are listed in tab l e 3 - 1 . table 3-1: pin function tables 3.1 address pins (a2, a1, a0) these pins are device address input pins. the address pins correspond to the least significant bits (lsb) of address bits. the most significant bits (msb) (a6, a5, a4, a3). this is shown in table 3-2 . 3.2 ground pin (gnd) the gnd pin is the system ground pin. 3.3 serial data line (sda) sda is a bidirectional input/output pin, used to serially transmit data to/from the host controller. this pin requires a pull-up resistor. (see section 4.0 ?serial communication? ). 3.4 serial clock line (sclk) the sclk is a clock input pin. all communication and timing is relative to the signal on this pin. the clock is generated by the host or master controller on the bus. (see section 4.0 ?serial communication? ). 3.5 open-drain temperature alert output (event) the mcp98242 event pin is an open-drain output. the device outputs a signal when the ambient temperature goes beyond the user-programmed temperature limit. (see section 5.2.3 ?event output configuration? ). 3.6 power pin (v dd) v dd is the power pin. the operating voltage range, as specified in the dc electrical specification table, is applied on this pin. 3.7 exposed thermal pad (ep) there is an internal electrical connection between the exposed thermal pad (ep) and the gnd pin; they must be connected to the same potential on the printed circuit board (pcb). dfn/tdfn/ udfn tssop symbol pin function package type 1 1 a0 slave address 2 2 a1 slave address 3 3 a2 slave address 44 gndground 5 5 sda serial data line 6 6 sclk serial clock line 7 7 event temperature alert output 88 v dd power pin 9 ? ep exposed thermal pad (ep); must be connected to v ss . sda gnd event sclk 1 2 3 4 8-pin tssop a0 v dd a1 a2 8 7 6 5 table 3-2: mcp98242 address byte device address code slave address a6 a5 a4 a3 a2 a1 a0 sensor 0011 xxx eeprom 1010 eeprom write-protect 0110 note: user-selectable address is shown by x. mcp98242 ds21996d-page 10 ? 2010 microchip technology inc. notes: ? 2010 microchip technology inc. ds21996d-page 11 mcp98242 4.0 serial communication 4.1 2-wire smbus/standard mode i 2 c? protocol-compatible interface the mcp98242 serial clock input (sclk) and the bidirectional serial data line (sda) form a 2-wire bidirectional smbus/standard mode i 2 c compatible communication port (refer to the input/output pin dc characteristics table and sensor and eeprom serial interface timing specifications table). the following bus protocol has been defined: table 4-1: mcp98242 serial bus protocol descriptions 4.1.1 data transfer data transfers are initiated by a start condition (start), followed by a 7-bit device address and a read/write bit. an acknowledge (ack) from the slave confirms the reception of each byte. each access must be terminated by a stop condition (stop). repeated communication is initiated after t b-free . this device does not support sequential register read/ write. each register needs to be addressed using the register pointer. this device supports the receive protocol. the register can be specified using the pointer for the initial read. each repeated read or receive begins with a start condition and address byte. the mcp98242 retains the previously selected register. therefore, it outputs data from the previously-specified register (repeated pointer specification is not necessary). 4.1.2 master/slave the bus is controlled by a master device (typically a microcontroller) that controls the bus access and generates the start and stop conditions. the mcp98242 is a slave device and does not control other devices in the bus. both master and slave devices can operate as either transmitter or receiver. however, the master device determines which mode is activated. 4.1.3 start/stop condition a high-to-low transition of the sda line (while sclk is high) is the start condition. all data transfers must be preceded by a start condition from the master. if a start condition is generated during data transfer, the mcp98242 resets and accepts the new start condition. a low-to-high transition of the sda line (while sclk is high) signifies a stop condition. if a stop condition is introduced during data transmission, the mcp98242 releases the bus. all data transfers are ended by a stop condition from the master. 4.1.4 address byte following the start condition, the host must transmit an 8-bit address byte to the mcp98242. the address for the mcp98242 temperature sensor is ? 0011,a2,a1,a0 ? in binary, where the a2, a1 and a0 bits are set externally by connecting the corresponding pins to v dd ? 1 ? or gnd ? 0 ?. the 7-bit address transmit- ted in the serial bit stream must match the selected address for the mcp98242 to respond with an ack. bit 8 in the address byte is a read/write bit. setting this bit to ? 1 ? commands a read operation, while ? 0 ? commands a write operation (see figure 4-1 ). term description master the device that controls the serial bus, typically a microcontroller. slave the device addressed by the master, such as the mcp98242. transmitter device sending data to the bus. receiver device receiving data from the bus. start a unique signal from master to initiate serial interface with a slave. stop a unique signal from the master to terminate serial interface from a slave. read/write a read or write to the mcp98242 registers. ack a receiver acknowledges (ack) the reception of each byte by polling the bus. nak a receiver not-acknowledges (nak) or releases the bus to show end-of-data (eod). busy communication is not possible because the bus is in use. not busy the bus is in the idle state, both sda and sclk remain high. data valid sda must remain stable before sclk becomes high in order for a data bit to be considered valid. during normal data transfers, sda only changes state while sclk is low. mcp98242 ds21996d-page 12 ? 2010 microchip technology inc. figure 4-1: device addressing. 4.1.5 data valid after the start condition, each bit of data in transmission needs to be settled for a time specified by t su-data before sclk toggles from low-to-high (see ?sensor and eeprom serial interface timing specifications? on page 5 ). 4.1.6 acknowledge (ack) each receiving device, when addressed, is obliged to generate an ack bit after the reception of each byte. the master device must generate an extra clock pulse for ack to be recognized. the acknowledging device pulls down the sda line for t su-data before the low-to-high transition of sclk from the master. sda also needs to remain pulled down for t h-data after a high-to-low transition of sclk. during read, the master must signal an end-of-data (eod) to the slave by not generating an ack bit (nak) once the last bit has been clocked out of the slave. in this case, the slave will leave the data line released to enable the master to generate the stop condition. 4.1.7 time out (mcp98242) if the sclk stays low or high for time specified by t out , the mcp98242 temperature sensor resets the serial interface. this dictates the minimum clock speed as specified in the smbus specification. however, the eeprom does not reset the serial interface. therefore, the master can hold the clock indefinitely to process data from the eeprom. 123456789 sclk sda 00 11 a2 a1 a0 start address byte slave address r/w mcp98242 response code address a c k ? 2010 microchip technology inc. ds21996d-page 13 mcp98242 5.0 functional description the mcp98242 temperature sensors consists of a band gap type temperature sensor, a delta-sigma ana- log-to-digital converter ( ??? adc), user-programmable registers and a 2-wire i 2 c/smbus protocol compatible serial interface. figure 5-1 shows a block diagram of the register structure. figure 5-1: functional block diagram. clear event 0.5c/bit 0.25c/bit 0.125c/bit 0.0625c/bit temperature t upper t lower configuration ?? adc band-gap temperature sensor event status output control critical event only event polarity event comp/int t crit capability temp. range accuracy output feature register pointer critical trip lock alarm win. lock bit shutdown hysteresis manufacturer id resolution memory control logic address standard array write- write-protect circuitry sense amp r/w control protected (00h-7fh) (80h-ffh) device id/rev selected resolution hv generator decoder array x address decoder y smbus/standard i 2 c? interface a0 a1 a2 event sda scl v dd gnd temperature sensor eeprom mcp98242 ds21996d-page 14 ? 2010 microchip technology inc. 5.1 registers the mcp98242 has several registers that are user-accessible. these registers include the capability register, configuration register, event temperature upper-boundary and lower-boundary trip registers, critical temperature trip register, temperature register, manufacturer identification register and device identification register. the temperature register is read-only, used to access the ambient temperature data. the data is loaded in parallel to this register after t conv . the event temperature upper-boundary and lower-boundary trip registers are read/writes. if the ambient temperature drifts beyond the user-specified limits, the mcp98242 outputs a signal using the event pin (refer to section 5.2.3 ?event output configuration? ). in addition, the critical temperature trip register is used to provide an additional critical temperature limit. the capability register is used to provide bits describing the mcp98242?s capability in measurement resolution, measurement range and device accuracy. the device configuration register provides access to configure the mcp98242?s various features. these registers are described in further detail in the following sections. the registers are accessed by sending a register pointer to the mcp98242 using the serial interface. this is an 8-bit write-only pointer. however, the three least significant bits are used as pointers and all unused bits (bits 7-3) need to be cleared or set to ? 0 ?. register 5-1 describes the pointer or the address of each register. register 5-1: register pointer (write only) w-0 w-0 w-0 w-0 w-0 w-0 w-0 w-0 ? ? ? ? pointer bits bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-4 writable bits: write ? 0 ?? bits 7-4 must always be cleared or written to ? 0 ?. this device has additional registers that are reserved for test and calibration. if these registers are accessed, the device may not perform according to the specification. bit 3-0 pointer bits: 0000 = capability register 0001 = configuration register (config) 0010 = event temperature upper-boundary trip register (t upper ) 0011 = event temperature lower-boundary trip register (t lower ) 0100 = critical temperature trip register (t crit ) 0101 = temperature register (t a ) 0110 = manufacturer id register 0111 = device id/revision register 1000 = resolution register 1xxx = reserved ? 2010 microchip technology inc. ds21996d-page 15 mcp98242 table 5-1: bit assignment summary for all registers (see section 5.4 ) register pointer (hex) msb/ lsb bit assignment 76 5 43210 0x00 msb 0 0 0 0 0 0 0 0 lsb 0 0 0 resolution range accuracy event 0x01 msb 0 0 0 0 0 hysteresis shdn lsb crt loc win loc int clr evt stat evt cnt evt sel evt pol evt pol 0x02 msb 0 0 0 sign 2 7 c 2 6 c 2 5 c 2 4 c lsb 2 3 c 2 2 c 2 1 c 2 0 c 2 -1 c 2 -2 c 0 0 0x03 msb 0 0 0 sign 2 7 c 2 6 c 2 5 c 2 4 c lsb 2 3 c 2 2 c 2 1 c 2 0 c 2 -1 c 2 -2 c 0 0 0x04 msb 0 0 0 sign 2 7 c 2 6 c 2 5 c 2 4 c lsb 2 3 c 2 2 c 2 1 c 2 0 c 2 -1 c 2 -2 c 0 0 0x05 msb t a ?? t crit t a ?? t upper t a ?? t lower sign 2 7 c 2 6 c 2 5 c 2 4 c lsb 2 3 c 2 2 c 2 1 c 2 0 c 2 -1 c 2 -2 c 0 0 0x06 msb 0 0 0 0 0 0 0 0 lsb 0 1 0 1 0 1 0 0 0x07 msb 0 0 1 0 0 0 0 0 lsb 0 0 0 0 0 0 0 1 0x08 lsb 0 0 0 0 0 0 0 1 mcp98242 ds21996d-page 16 ? 2010 microchip technology inc. 5.1.1 capability register this is a read-only register used to identify the temperature sensor capability. in this case, the mcp98242 is capable of providing temperature at 0.25c resolution, measuring temperature below and above 0c, providing 1c and 2c accuracy over the active and monitor temperature ranges (respectively) and providing user-programmable temperature event boundary trip limits. register 5-2 describes the capability register. these functions are described in further detail in the following sections. register 5-2: capability register (read-only) ? address ?0000 0000?b u-0 u-0 u-0 u-0 u-0 u-0 u-0 u-0 ???????? bit 15 bit 8 u-0 u-0 u-0 r-0 r-1 r-1 r-1 r-1 ? ? ? resolution meas range accuracy temp alarm bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 15-5 unimplemented: read as ? 0 ? bit 4-3 resolution: 00 = 0.5c 01 = 0.25c (power-up default) 10 = 0.125c 11 = 0.0625c these bits reflect the selected resolution (see section 5.2.3.3 ?temperature resolution? ) bit 2 temperature measurement range (meas. range): 0 =t a ?? 0 (decimal) for temperature below 0c ? 1 = the part can measure temperature below 0c (power-up default) bit 1 accuracy: 0 =accuracy ?? 2c from +75c to +95c (active range) and 3c from +40c to +125c (monitor range) 1 =accuracy ?? 1c from +75c to +95c (active range) and 2c from +40c to +125c (monitor range) bit 0 temperature alarm: 0 = no defined function (this bit will never be cleared or set to ? 0 ?). 1 = the part has temperature boundary trip limits (t upper /t lower /t crit registers) and a temperautre event output (jc 42.4 required feature). ? 2010 microchip technology inc. ds21996d-page 17 mcp98242 figure 5-2: timing diagram for reading the capability register (see section 4.0 ?serial communication? ). sda a c k 0011 a capability pointer 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte a c k 0011 a msb data a c k n a k s p 2 a 1 a 0 12345678 12345678 12345678 address byte lsb data r mcp98242 mcp98242 mcp98242 master master w sda sclk 000 00000 000 00001 111 mcp98242 ds21996d-page 18 ? 2010 microchip technology inc. 5.1.2 sensor configuration register (config) the mcp98242 has a 16-bit configuration register (config) that allows the user to set various functions for a robust temperature monitoring system. bits 10 thru 0 are used to select event output boundary hysteresis, device shutdown or low-power mode, temperature boundary and critical temperature lock, temperature event output enable/disable. in addition, the user can select the event output condition (output set for t upper and t lower temperature boundary or t crit only), read event output status and set event output polarity and mode (comparator output or interrupt output mode). the temperature hysteresis bits 10 and 9 can be used to prevent output chatter when the ambient temperature gradually changes beyond the user-specified temperature boundary (see section 5.2.2 ?temperature hysteresis (t hyst )? . the continuous conversion or shutdown mode is selected using bit 8. in shutdown mode, the band gap temperature sensor circuit stops converting temperature and the ambient temperature register (t a ) holds the previous successfully converted temperature data (see section 5.2.1 ?shutdown mode? ). bits 7 and 6 are used to lock the user-specified boundaries t upper , t lower and t crit to prevent an accidental rewrite. bits 5 thru 0 are used to configure the temperature event output pin. all functions are described in register 5-3 (see section 5.2.3 ?event output configuration? ). register 5-3: co nfiguration register (config) ? address ?0000 0001?b u-0 u-0 u-0 u-0 u-0 r/w-0 r/w-0 r/w-0 ????? t hyst shdn bit 15 bit 8 r/w-0 r/w-0 r/w-0 r-0 r/w-0 r/w-0 r/w-0 r/w-0 crit. lock win. lock int. clear event stat. event cnt. event sel. event pol. event mod. bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 15-11 unimplements: read as ? 0 ? bit 10-9 t upper and t lower limit hysteresis (t hyst ): 00 = 0c (power-up default) 01 = 1.5c 10 = 3.0c 11 = 6.0c this bit cannot be altered when either of the lock bits are set (bit 6 and bit 7), refer to section 5.2.3 ?event output configuration? . bit 8 shutdown mode (shdn): 0 = continuous conversion (power-up default) 1 = shutdown (low-power mode) in shutdown, all power-consuming activities are disabled, though all registers can be written to or read. this bit cannot be set ? 1 ? when either of the lock bits is set (bit 6 and bit 7). however, it can be cleared ? 0 ? for continuous conversion while locked. (refer to section 5.2.1 ?shutdown mode? ) ? 2010 microchip technology inc. ds21996d-page 19 mcp98242 bit 7 t crit lock bit (crit. lock): 0 = unlocked. t crit register can be written. (power-up default) 1 =locked. t crit register cannot be written when enabled, this bit remains set ? 1 ? or locked until cleared by internal reset ( section 5.4 ?sum- mary of temperature sensor power-on default? ). this bit does not require a double-write. bit 6 t upper and t lower window lock bit (win. lock): 0 = unlocked. t upper and t lower registers can be written. (power-up default) 1 =locked. t upper and t lower registers cannot be written when enabled, this bit remains set ? 1 ? or locked until cleared by internal reset ( section 5.4 ?sum- mary of temperature sensor power-on default? ). this bit does not require a double-write. bit 5 interrupt clear (int. clear) bit: 0 = no effect (power-up default) 1 = clear interrupt output. when read this bit returns ? 0 ? bit 4 event output status (event stat.) bit: 0 = event output is not asserted by the device (power-up default) 1 = event output is asserted as a comparator/interrupt or critical temperature output bit 3 event output control (event cnt.) bit: 0 = disabled (power-up default) 1 = enabled this bit cannot be altered when either of the lock bits is set (bit 6 and bit 7). bit 2 event output select (event sel.) bit: 0 = event output for t upper , t lower and t crit (power-up default) 1 = t a > t crit only. (t upper and t lower temperature boundaries are disabled.) when the alarm window lock bit is set, this bit cannot be altered until unlocked (bit 6). bit 1 event output polarity (event pol.) bit: 0 = active-low (power-up default) 1 = active-high this bit cannot be altered when either of the lock bits is set (bit 6 and bit 7). bit 0 event output mode (event mod.) bit: 0 = comparator output (power-up default) 1 = interrupt output this bit cannot be altered when either of the lock bits is set (bit 6 and bit 7). register 5-3: co nfiguration register (config) ? address ?0000 0001?b mcp98242 ds21996d-page 20 ? 2010 microchip technology inc. figure 5-3: timing diagram for writing and reading from the configuration register (see section 4.0 ?serial communication? ). sda a c k 0011 a configuration pointer 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte a c k 0011 a msb data a c k n a k s p 2 a 1 a 0 12345678 12345678 12345678 address byte lsb data r mcp98242 mcp98242 mcp98242 master master w sda sclk 001 00000 000 00001 000 ? reading the config register. ? writing to the config register to enable the event output pin <0000 0000 0000 1000>b. sda a c k 0011 a 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte w mcp98242 mcp98242 msb data a c k a c k p 12345678 12345678 lsb data configuration pointer mcp98242 mcp98242 001 00000 000 00001 000 note: it is not necessary to select the register pointer if it was set from the previous read/ write. ? 2010 microchip technology inc. ds21996d-page 21 mcp98242 5.1.3 upper/lower/critical temperature limit registers (t upper /t lower /t crit ) the mcp98242 has a 16-bit read/write event output temperature upper-boundary trip register (t upper ), a 16-bit lower-boundary trip register (t lower ) and a 16-bit critical boundary trip register (t crit ) that contains 11-bit data in two?s complement format (0.25 c). this data represents the maximum and minimum temperature boundary or temperature window that can be used to monitor ambient temperature. if this feature is enabled ( section 5.1.2 ?sensor configuration register (config)? ) and the ambient temperature exceeds the specified boundary or window, the mcp98242 asserts an event output. (refer to section 5.2.3 ?event output configuration? ). register 5-4: upper/lower/critical temperature limit register (t upper /t lower / t crit ) ? address ?0000 0010?b/?0000 0011?b ? ?0000 0100?b u-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ???sign2 7 c 2 6 c 2 5 c 2 4 c bit 15 bit 8 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 u-0 u-0 2 3 c 2 2 c 2 1 c 2 0 c 2 -1 c 2 -2 c ? ? bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 15-13 unimplemented: read as ? 0 ? bit 12 sign: 0 =t a ?? 0c ? 1 =t a ? 0c bit 11-2 t upper /t lower /t crit : temperature boundary trip data in two?s complement format. bit 1-0 unimplemented: read as ? 0 ? note: this table shows two 16-bit registers for t upper , t lower and t crit located at ? 0000 0010b ?, ? 0000 0011b ? and ? 0000 0100b ?, respectively. mcp98242 ds21996d-page 22 ? 2010 microchip technology inc. figure 5-4: timing diagram for writing and reading from the t upper register (see section 4.0 ?serial communication? ). sda a c k 0011 a t upper pointer 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte a c k 0011 a msb data a c k n a k s p 2 a 1 a 0 12345678 12345678 12345678 address byte lsb data r mcp98242 mcp98242 mcp98242 master master w sda sclk 010 00000 101 10100 000 ? reading from the t upper register. ? writing 90c to the t upper register <0000 0101 1010 0000>b. sda a c k 0011 a 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte w mcp98242 mcp98242 msb data a c k a c k p 12345678 12345678 lsb data t upper pointer mcp98242 mcp98242 010 00000 101 10100 000 note: it is not necessary to select the register pointer if it was set from the previous read/write. ? 2010 microchip technology inc. ds21996d-page 23 mcp98242 5.1.4 ambient temperature register (t a ) the mcp98242 uses a band gap temperature sensor circuit to output analog voltage proportional to absolute temperature. an internal ?? adc is used to convert the analog voltage to a digital word. the converter resolution is set to 0.25 c + sign (11-bit data). the digital word is loaded to a 16-bit read-only ambient temperature register (t a ) that contains 11-bit temperature data in two?s complement format. the t a register bits (bits 12 thru 0) are double-buffered. therefore, the user can access the register while, in the background, the mcp98242 performs an analog-to- digital conversion. the temperature data from the ?? adc is loaded in parallel to the t a register at t conv refresh rate. the t a magnitude in decimal to ambient temperature conversion is shown in equation 5-1 : equation 5-1: decimal code to temperature conversion in addition, the t a register uses three bits (bits 15, 14 and 13) to reflect the event pin state. this allows the user to identify the cause of the event output trigger (see section 5.2.3 ?event output configuration? ); bit 15 is set to ? 1 ? if t a is greater than or equal to t crit , bit 14 is set to ? 1 ? if t a is greater than t upper and bit 13 is set to ? 1 ? if t a is less than t lower . the t a register bit assignment and boundary conditions are described in register 5-5 . t a code 2 4 ? ? = where: t a = ambient temperature (c) code = mcp98242 temperature output magnitude in decimal (bits 0-11) register 5-5: ambient temperature register (t a ) ? address ?0000 0101?b r-0 r-0 r-0 r-0 r-0 r-0 r-0 r-0 t a vs. t crit t a vs. t upper t a vs. t lower sign 2 7 c 2 6 c 2 5 c 2 4 c bit 15 bit 8 r-0 r-0 r-0 r-0 r-0 r-0 r-0 r-0 2 3 c 2 2 c 2 1 c 2 0 c 2 -1 c 2 -2 c ? ? bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 15 t a vs. t crit ( 1 ) bit: 0 =t a ?? t crit 1 =t a ?? t crit bit 14 t a vs. t upper ( 1 ) bit: 0 =t a ?? t upper 1 =t a ?? t upper bit 13 t a vs. t lower ( 1 ) bit: 0 =t a ?? t lower 1 =t a ?? t lower bit 12 sign bit: 0 =t a ?? 0c ? 1 =t a ? 0c bit 11-2 ambient temperature (t a ) bits: 10-bit ambient temperature data in two?s complement format. bit 1-0 t a : data in 2?s complement format. depending on the status of the resolution register ( register 5-8 ), these bits may display 2 -3 c (0.125c) and 2 -4 c (0.0625c), respectively. note 1: not affected by the status of the event output configuration (bits 5 to 0 of config), register 5-3 . mcp98242 ds21996d-page 24 ? 2010 microchip technology inc. figure 5-5: timing diagram for reading +25.25c temperature from the t a register (see section 4.0 ?serial communication? ). sda a c k 0011 a t a pointer 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte a c k 0011 a msb data a c k n a k s p 2 a 1 a 0 12345678 12345678 12345678 address byte lsb data r mcp98242 mcp98242 mcp98242 master master w sda sclk 101 00000 001 10010 100 note: it is not necessary to select the register pointer if it was set from the previous read/ write. ? 2010 microchip technology inc. ds21996d-page 25 mcp98242 5.1.5 manufacturer id register this register is used to identify the manufacturer of the device in order to perform manufacturer specific operation. the manufacturer id for the mcp98242 is 0x0054 (hexadecimal). figure 5-6: timing diagram for reading the manufacturer id register (see section 4.0 ?serial communication? ). register 5-6: manufacturer id register (read-only) ? address ?0000 0110?b r-0 r-0 r-0 r-0 r-0 r-0 r-0 r-0 manufacturer id bit 15 bit 8 r-0 r-1 r-0 r-1 r-0 r-1 r-0 r-0 manufacturer id bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 15-0 device manufacturer identification number . sda a c k 0011 a manuf. id pointer 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte a c k 0011 a msb data a c k n a k s p 2 a 1 a 0 12345678 12345678 12345678 address byte lsb data r mcp98242 mcp98242 mcp98242 master master w sda sclk 110 00000 000 01010 100 note: it is not necessary to select the register pointer if it was set from the previous read/ write. mcp98242 ds21996d-page 26 ? 2010 microchip technology inc. 5.1.6 device id and revision register the upper byte of this register is used to specify the device identification and the lower byte is used to specify device revision. the device id for the mcp98242 is 0x21 (hex). the revision begins with 0x00 (hex) for the first release, with the number being incremented as revised versions are released. figure 5-7: timing diagram for reading device id and device revision register (see section 4.0 ?serial communication? ). register 5-7: device id and device revision (read-only) ? address ?0000 0111?b r-0 r-0 r-1 r-0 r-0 r-0 r-0 r-0 device id bit 15 bit 8 r-0 r-0 r-0 r-0 r-0 r-0 r-0 r-1 device revision bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 15-8 device id: bit 15 to bit 8 are used for device id bit 7-0 device revision: bit 7 to bit 0 are used for device revision sda a c k 0011 a device id pointer 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte a c k 0011 a msb data a c k n a k s p 2 a 1 a 0 12345678 12345678 12345678 address byte lsb data r mcp98242 mcp98242 mcp98242 master master w sda sclk 111 00100 000 00000 000 note: it is not necessary to select the register pointer if it was set from the previous read/ write. ? 2010 microchip technology inc. ds21996d-page 27 mcp98242 5.1.7 resolution register this register allows the user to change the sensor resolution (see section 5.2.3.3 ?temperature resolution? ). the por default resolution is 0.25c. the selected resolution is also reflected in the capability register (see register 5-2 ). figure 5-8: timing diagram for changing t a resolution to 0.0625c <0000 0011>b (see section 4.0 ?serial communication? ). register 5-8: resolution ? address ?0000 1000?b u-0 u-0 u-0 u-0 u-0 u-0 r/w-0 r/w-0 ?????? resolution bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-2 unimplemented: read as ? 0 ? bit 1-0 resolution: 00 = lsb = 0.5c (t conv = 30 ms typical) 01 = lsb = 0.25c (power-up default, t conv = 65 ms typical) 10 = lsb = 0.125c (t conv = 130 ms typical) 11 = lsb = 0.0625c (t conv = 260 ms typical) sda a c k 0011 a a c k s 2 a 1 a 0 12345678 12345678 sclk address byte w mcp98242 mcp98242 a c k p 12345678 data resolution pointer mcp98242 00001 000 00000 011 mcp98242 ds21996d-page 28 ? 2010 microchip technology inc. 5.2 sensor feature description 5.2.1 shutdown mode shutdown mode disables all power-consuming activities (including temperature sampling operations) while leaving the serial interface active. this mode is selected by setting bit 8 of config to ? 1 ?. in this mode, the device consumes i shdn . it remains in this mode until bit 8 is cleared ? 0 ? to enable continuous conversion mode, or until power is recycled. the shutdown bit (bit 8) cannot be set to ? 1 ? while bits 6 and 7 of config (lock bits) are set to ? 1 ?. however, it can be cleared ? 0 ? or returned to continuous conversion while locked. in shutdown mode, all registers can be read or written. however, the serial bus activity increases the shutdown current. in addition, if the device is shutdown while the event pin is asserted as active-low or deasserted active-low (see section 5.2.3.1 ?comparator mode? ), the device will retain the active-low state. this increases the shutdown current due to the additional event output pull-down current. 5.2.2 temperature hysteresis (t hyst ) a hysteresis of 0c, 1.5c, 3c or 6c can be selected for the t upper , t lower and t crit temperate boundaries using bits 10 and 9 of config. the hysteresis applies for decreasing temperature only (hot to cold), or as temperature drifts below the specified limit. the t upper , t lower and t crit boundary conditions are described graphically in figure 5-2 . 5.2.3 event output configuration the event output can be enabled using bit 3 of config (event output control bit) and can be configured as either a comparator output or as interrupt output mode using bit 0 of config (event mode). the polarity can also be specified as an active-high or active-low using bit 1 of config (event polarity). when the ambient temperature increases above the critical temperature limit, the event output is forced to a comparator output (regardless of bit 0 of config). when the temperature drifts below the critical temperature limit minus hysteresis, the event output automatically returns to the state specified by bit 0 of config. the status of the event output can be read using bit 4 of config (event status). bit 7 and 6 of the config register can be used to lock the t upper , t lower and t crit registers. the bits prevent false triggers at the event output due to an accidental rewrite to these registers. the event output can also be used as a critical temperature output using bit 2 of config (critical output only). when this feature is selected, the event output becomes a comparator output. in this mode, the interrupt output configuration (bit 0 of config) is ignored. 5.2.3.1 comparator mode comparator mode is selected using bit 0 of config. in this mode, the event output is asserted as active-high or active-low using bit 1 of config. figure 5-2 shows the conditions that toggle the event output. if the device enters shutdown mode with asserted event output, the output remains asserted during shutdown. the device must be operating in continuous conversion mode for t conv ; the t a vs. t upper , t lower and t crit boundary conditions need to be satisfied in order for the event output to deassert. comparator mode is useful for thermostat-type applications, such as turning on a cooling fan or triggering a system shutdown when the temperature exceeds a safe operating range. 5.2.3.2 interrupt mode in the interrupt mode, the event output is asserted as active-high or active-low (depending on the polarity configuration) when t a drifts above or below t upper and t lower limits. the output is deasserted by setting bit 5 (interrupt clear) of config. note that when switching from comparator mode to interrupt mode, it is recommended to send interrupt clear command (set bit 5) to reset the interrupt flag. shutting down the device will not reset or deassert the event output. this mode cannot be selected when the event output is used as critical temperature output only, using bit 2 of config. this mode is designed for interrupt driven microcontroller-based systems. the microcontroller receiving the interrupt will have to acknowledge the interrupt by setting bit 5 of config register from the mcp98242. 5.2.3.3 temperature resolution the mcp98242 is capable of providing a temperature data with 0.5c to 0.0625c resolution. the resolution can be selected using the resolution register ( register 5-8 ) which is located in address ? 00001000 ?b. this address location is not specified in jedec standard jc42.4. however, it provides additional flexibility while being functionally compatible with jc42.4 and provide a 0.25c resolution at 125 ms (maximum). the selected resolution can be read by user using bit 4 and bit 3 of the capability register ( register 5-2 ). a 0.25c resolution is set as por default by factory. ? 2010 microchip technology inc. ds21996d-page 29 mcp98242 table 5-2: temperature conversion time figure 5-9: event output condition. resolution t conv (ms) samples/sec (typical) 0.5c 30 33 0.25c (por default) 65 15 0.125c 130 8 0.0625c 260 4 t upper t lower event output t crit t a t upper - t hyst (active-low) comparator interrupt s/w int. clear critical only t crit - t hyst 1 2 3 4 5 6 note event output boundary conditions event output t a bits comparator interrupt critical 15 14 13 1t a ?? t lower hlh 000 2t a ? t lower - t hyst llh 001 3t a ?? t upper llh 010 4 t a ? t upper - t hyst hlh 000 5 t a ? t crit lll 110 6t a ? t crit - t hyst lhh 010 * when t a ?? t crit and t a ? t crit - t hyst the event output is comparator mode and bits 0 of config (event output mode) is ignored. t lower -t hyst t lower -t hyst t upper - t hyst 1 3 4 2 note: * mcp98242 ds21996d-page 30 ? 2010 microchip technology inc. 5.3 eeprom feature description 5.3.1 byte write to write a byte in the mcp98242 eeprom, the master has to specify the memory location or address. once the address byte is transmitted correctly followed by a word address, the word address is stored in the eeprom address pointer. the following byte is data to be stored in the specified memory location. figure 5-10 shows the timing diagram. figure 5-10: timing diagram for byte write (see section 4.0 ?serial communication? ). sda a c k 1010 a a c k s 2 a 1 a 0 12345678 12345678 sclk address byte w mcp98242 mcp98242 a c k p 12345678 data word address mcp98242 xxxxx xx x x x xxx xxx ? 2010 microchip technology inc. ds21996d-page 31 mcp98242 5.3.2 page write the write address byte, word address and the first data byte are transmitted to the mcp98242 in the same way as in a byte write. instead of generating a stop condition, the master transmits up to 15 additional data bytes to the mcp98242, which are temporarily stored in the on-chip page buffer and will be written into the memory after the master has transmitted a stop condition. upon receipt of each word, the four lower order address pointer bits are internally incremented by one. the higher order four bits of the word address remain constant. if the master should transmit more than 16 bytes prior to generating the stop condition, the address counter will roll over and the previously received data will be overwritten. as with the byte write operation, once the stop condition is received, an internal write cycle will begin ( figure 5-11 ). figure 5-11: timing diagram for page write (see section 4.0 ?serial communication? ). note: page write operations are limited to writing bytes within a single physical page, regardless of the number of bytes actually being written. physical page boundaries start at addresses that are integer multiples of the page buffer size (or ?page size?) and end at addresses that are integer multiples of [page size - 1]. if a page write command attempts to write across a physical page boundary, the result is that the data wraps around to the beginning of the current page (overwriting data previously stored there), instead of being written to the next page, as might be expected. it is therefore necessary for the application software to prevent page write operations that would attempt to cross a page boundary. sda a c k 1010 a xxxx a c k s 2 a 1 a 0 12345678 12345678 sclk x address byte w mcp98242 mcp98242 data at (n) a c k p 12345678 12345678 data at (n+1) word address (n) mcp98242 mcp98242 xxx xxxxx xxx xxxxx xxx a c k data at (n+15) mcp98242 xxx xxx a c k note: ?n? is the initial address for a page. mcp98242 ds21996d-page 32 ? 2010 microchip technology inc. 5.3.3 write protection the mcp98242 has a software write-protect (swp) feature that allows the lower half array (addresses 00h -7f h ) to be write-protected or permanently write-protected (pwp). the write-protected area can be cleared by sending clear write-protect (cwp) command. however, once the pwp is executed the protected memory can not be cleared. the device will not respond to the cwp command. to access write protection, the device address code of the address byte is set to ? 0110 ? instead of ? 1010 ?. the ? 1010 ? address code is used to access the mem- ory area and the ? 0110 ? address code is used to access the write protection. once the device is write- protected it will not acknowledge certain commands. table 5-3 shows the corresponding address bytes for the write-protect feature. table 5-3: write-protect device addressing table 5-4: device response when writing data or accessing swp/cwp/pwp eeprom operation address pins address byte a2 a1 a0 address code slave address r/w a2 a1 a0 swp write gnd gnd v hi_a0 0110 0 0 1 0 read 1 cwp write gnd v dd v hi_a0 0110 0 1 1 0 read 1 pwp ( note )writexxx 0110 x x x 0 read 1 note: the address pins are ?x? or don?t cares. however, the slave address bits need to match the address pins. status command ack address ack data byte ack write cycle not protected swp/cwp/pwp ack x ack x ack yes page/byte write ack address ack data ack yes protected with swp swp noack x noack x noack no cwp ack x ack x ack yes pwp ack x ack x ack yes page/byte write lower 128 bytes ack address ack data noack no permanently protected swp/cwp/pwp noack x noack x noack no page/byte write lower 128 bytes ack address ack data noack no note: x is defined as ?don?t care?. ? 2010 microchip technology inc. ds21996d-page 33 mcp98242 5.3.3.1 software write-protect (swp) the swp feature is invoked by writing to the write-protect register. this is done by sending an address byte similar to a normal write command. figure 5-14 shows the timing diagram. swp can be cleared using the cwp command. see section 5.3.3.2 ?clear write-protect (cwp)? . the slave address bits need to correspond to the address pin logic configuration. for swp, a high voltage v hi_wp needs to be applied to the a0 pin and the corresponding slave address needs to be set to ? 1 ?, as shown in tab l e 5 - 3 . both a2 and a1 pins are grounded and the corresponding slave address bits are set to ? 0 ?. the device response in this mode is shown in table 5-4 and ta bl e 5 - 5 . figure 5-12: timing diagram for setting software write-protect (see section 4.0 ?serial communication? ). 5.3.3.2 clear write-protect (cwp) the cwp feature is invoked by writing to the clear write-protect register. this is done by sending an address byte similar to a normal write command. figure 5-14 shows the timing diagram. cwp clears swp only. pwp can not be cleared using this command. the slave address bits need to correspond to the address pin logic configuration. for cwp, a high voltage v hi_wp needs to be applied to the a0 pin and the corresponding slave address needs to be set to ? 1 ?. the a1 pin is set to v dd and the corresponding slave address bit is set to ? 1 ?. and a2 pin is set to ground and the corresponding slave address bits are set to ? 0 ?. table 5-3 shows the bit configuration. the device response in this mode is shown in ta b l e 5 - 4 and table 5-5 . figure 5-13: timing diagram for setting clear write-protect (see section 4.0 ?serial communication? ). sda a c k 0110 a c k s 12345678 12345678 sclk address byte w mcp98242 mcp98242 a c k p 12345678 data word address mcp98242 xxxxx xxx xxxxx xxx 001 note: apply v hi_wp at a0 pin and connect gnd to a1 and a2 pins to initiate swp cycle. sda a c k 0110 a c k s 12345678 12345678 sclk address byte w mcp98242 mcp98242 a c k p 12345678 data word address mcp98242 xxxxx xxx xxxxx xxx 011 note: apply v hi_wp at a0 pin, apply v dd at a1 pin, connect a2 pin to gnd to initiate cwp cycle. mcp98242 ds21996d-page 34 ? 2010 microchip technology inc. 5.3.3.3 pwp (permanent write-protect) once the pwp register is written, the lower half of the memory will be permanent protected and the device will not acknowledge any command. the protected area of the memory can not be cleared, reversed, or re-written. if a write is attempted to the protected area, the device will acknowledge the address byte and word address but not the data byte. (see ta bl e 5 - 4 and table 5-5 ). unlike swp and cwp, a v hi_wp is not applied on the a0 pin to execute pwp. the state of a2, a1, and a0 is user selectable. however, the address pin states need to match the slave address bits, as shown in ta b l e 5 - 3 . figure 5-14: timing diagram for setting permanently write-protect (see section 4.0 ?serial communication? ). note: once the permanent write-protect is executed, it cannot be reversed, even if the device power is cycled. sda a c k 0110 a a c k s 2 a 1 a 0 12345678 12345678 sclk address byte w mcp98242 mcp98242 a c k p 12345678 data word address mcp98242 xxxxx xxx xxxxx xxx note: unlike swp and cwp, a v hi_wp is not applied on the a0 pin to execute pwp. ? 2010 microchip technology inc. ds21996d-page 35 mcp98242 5.3.4 read operation read operations are initiated in the same way as write operations, with the exception that the r/w bit of the slave address is set to ? 1 ?. there are three basic types of read operations: current address read, random read, and sequential read. table 5-5: device response when reading swp/cwp/pwp 5.3.4.1 current address read the mcp98242 contains an address counter that maintains the address of the last word accessed, internally incremented by ? 1 ?. therefore, if the previous access (either a read or write operation) was to address n , the next current address read operation would access data from address n+1 . upon receipt of the slave address with r/w bit set to ? 1 ?, the mcp98242 issues an acknowledge and transmits the 8-bit data word. the master will not acknowledge (nak) the transfer but does generate a stop condition and the mcp98242 discontinues transmission ( figure 5-15 ). figure 5-15: reading current word address (see section 4.0 ?serial communication? ). status command ack address ack data byte ack not protected swp/cwp/pwp ack x noack x noack protected with swp swp noack x noack x noack cwp ack x noack x noack pwp ack x noack x noack permanently protected swp/cwp/pwp noack x noack x noack note: x is defined as ?don?t care?. 1010 a a c k n a k s p 2 a 1 a 0 12345678 12345678 address byte current word address r mcp98242 master sda sclk 00000 000 note: in this example, the current word address is the previously accessed address location n plus 1. mcp98242 ds21996d-page 36 ? 2010 microchip technology inc. 5.3.4.2 random read random read operations allow the master to access any memory location in a random manner. to perform this type of read operation, the word address must first be set. this is done by sending the word address to the mcp98242 as part of a write operation. once the word address is sent, the master generates a start condition following the acknowledge. this terminates the write operation, but not before the internal address pointer is set. the master then issues the address byte again, but with the r/w bit set to a ? 1 ?. the mcp98242 then issues an acknowledge and transmits the 8-bit data word. the master will not acknowledge the transfer but does generate a stop condition and the mcp98242 discontinues transmission ( figure 5-16 ). figure 5-16: timing diagram for random read (see section 4.0 ?serial communication? ). sda a c k 1010 a word address (n) 0000 a c k s 2 a 1 a 0 12345678 12345678 sclk 0 address byte mcp98242 mcp98242 w 000 1010 a a c k n a k s p 2 a 1 a 0 12345678 12345678 address byte data at (n) r mcp98242 master sda sclk xxxxx xxx note: in this example, ?n? is the current address word which ?00?h and the data is the byte at address ?n?. ? 2010 microchip technology inc. ds21996d-page 37 mcp98242 5.3.4.3 sequential read sequential reads are initiated in the same way as a random read, with the exception that after the mcp98242 transmits the first data byte, the master issues an acknowledge, as opposed to a stop condi- tion in a random read. this directs the mcp98242 to transmit the next sequentially addressed 8-bit word ( figure 5-17 ). to provide sequential reads, the mcp98242 contains an internal address pointer, which is incremented by one at the completion of each operation. this address pointer allows the entire memory contents to be serially read during one operation. figure 5-17: timing diagram for sequential read (see section 4.0 ?serial communication? ). 5.3.5 standby mode the design will incorporate a low-power standby mode (i shdn ). standby mode will be entered after a normal termination of any operation and after all internal functions are complete. this would include any error conditions occurring, such as improper number of clock cycles or improper instruction byte as defined previously. sda a c k 1010 a xxxx a c k s 2 a 1 a 0 12345678 12345678 sclk x address byte r mcp98242 mcp98242 data at (n+1) a c k 12345678 12345678 data at (n+2) data (n) 1 mcp98242 mcp98242 xxx xxxxx xxx xxxxx xxx data at (n+m) (1) xxx xxx a c k note 1: ?n? is the initial address location and ?m? is the final address location (?n+m? < 256). n a k p master mcp98242 ds21996d-page 38 ? 2010 microchip technology inc. 5.4 summary of temperature sensor power-on default the mcp98242 temperature sensor has an internal power-on reset (por) circuit. if the power supply voltage v dd glitches down to the v por threshold, the device resets the registers to the power-on default settings. table 5-6 shows the power-on default summary. table 5-6: power-on defaults registers default register data (hexadecimal) power-up default register description address (hexadecimal) register label 0x00 capability 0x000f 0.25 measures temperature below 0c 1c accuracy over active range temperature event output 0x01 config 0x0000 comparator mode active-low output event and critical output output disabled event not asserted interrupt cleared event limits unlocked critical limit unlocked continuous conversion 0c hysteresis 0x02 t upper 0x0000 0c 0x03 t lower 0x0000 0c 0x04 t crit 0x0000 0c 0x05 t a 0x0000 0c 0x06 manufacturer id 0x0054 0x0054 (hex) 0x07 device id/ device revision 0x2001 0x2001 (hex) 0x08 resolution 0x01 0x01 (hex) ? 2010 microchip technology inc. ds21996d-page 39 mcp98242 6.0 applications information 6.1 connecting to the serial bus the sda and sclk serial interface pins are open-drain pins that require pull-up resistors. this configuration is shown in figure 6-1 . figure 6-1: pull-up resistors on serial interface. the number of devices connected to the bus is limited only by the maximum rise and fall times of the sda and sclk lines. unlike i 2 c specifications, smbus does not specify a maximum bus capacitance value. rather, the smbus specification requires that the maximum current through the pull-up resistor be 350 a and minimum 100 a. because of this, the value of the pull-up resistors will vary depending on the system?s bias voltage (v dd ). the pull-up resistor values for a 3.3 v system ranges 9 k ? to 33 k ? . minimizing bus capacitance is still very important as it directly affects the rise and fall times of the sda and sclk lines. although smbus specifications only require the sda and sclk lines to pull-down 350 a, with a maximum voltage drop of 0.4 v, the mcp98242 is designed to meet a maximum voltage drop of 0.4 v, with 3 ma of current. this allows lower pull-up resistor values to be used, allowing the mcp98242 to handle higher bus capacitance. in such applications, all devices on the bus must meet the same pull-down current requirements. a possible configuration using multiple devices on the smbus is shown in figure 6-2 . figure 6-2: multiple devices on dimm smbus. 6.2 layout considerations the mcp98242 does not require any additional components besides the master controller in order to measure temperature. however, it is recommended that a decoupling capacitor of 0.1 f to 1 f be used between the v dd and gnd pins. a high-frequency ceramic capacitor is recommended. it is necessary for the capacitor to be located as close as possible to the power and ground pins of the device in order to provide effective noise protection. 6.3 thermal considerations a potential for self-heating errors can exist if the mcp98242 sda, sclk and event lines are heavily loaded with pull-ups (high current). typically, the self-heating error is negligible because of the relatively small current consumption of the mcp98242. a temperature accuracy error of approximately 0.5c could result from self-heating if the communication pins sink/source the maximum current specified. for example, if the event output is loaded to maximum i ol , equation 6-1 can be used to determine the effect of self-heating. equation 6-1: effect of self-heating at room temperature (t a = +25c) with maximum i dd = 500 a and v dd = 3.6v, the self-heating due to power dissipation t ? is 0.2c for the dfn-8 package and 0.5c for the tssop-8 package. sda sclk v dd r r microcontroller mcp98242 event r master slave sda sclk mcp98242 temperature sensor 24lcs52 eeprom t ? ? ja v dd i dd v ol_event i ol_event v ol_sda i ol_sda ? + ? + ? ?? = where: t ? =t j - t a t j = junction temperature t a = ambient temperature ? ja = package thermal resistance v ol_event, sda = event and sda output v ol (0.4 v max ) i ol_event, sda = event and sda output i ol (3 ma max ) mcp98242 ds21996d-page 40 ? 2010 microchip technology inc. notes: ? 2010 microchip technology inc. ds21996d-page 41 mcp98242 7.0 packaging information 7.1 package marking information 8-lead dfn (mc) example : xxx yww nn abj 010 25 8-lead tssop (st) example: xxxx yyww nnn 242b e010 256 legend: xx...x customer-specific information y year code (last digit of calendar year) yy year code (last 2 digits of calendar year) ww week code (week of january 1 is week ?01?) nnn alphanumeric traceability code pb-free jedec designator for matte tin (sn) * this package is pb-free. the pb-free jedec designator ( ) can be found on the outer packaging for this package. note : in the event the full microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. 3 e 3 e 8-lead tdfn (mny) example : xxx yww nn abx 010 25 8-lead udfn (muy) example : xxx yww nn abx 010 25 mcp98242 ds21996d-page 42 ? 2010 microchip technology inc. d n e note 1 1 2 exposed pad note 1 2 1 d2 k l e2 n e b a3 a1 a note 2 bottom view top view ? 2010 microchip technology inc. ds21996d-page 43 mcp98242 mcp98242 ds21996d-page 44 ? 2010 microchip technology inc. note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging ? 2010 microchip technology inc. ds21996d-page 45 mcp98242 note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging mcp98242 ds21996d-page 46 ? 2010 microchip technology inc. ? 2010 microchip technology inc. ds21996d-page 47 mcp98242 mcp98242 ds21996d-page 48 ? 2010 microchip technology inc. ? 2010 microchip technology inc. ds21996d-page 49 mcp98242 d n e e1 note 1 12 b e c a a1 a2 l1 l mcp98242 ds21996d-page 50 ? 2010 microchip technology inc. note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging ? 2010 microchip technology inc. ds21996d-page 51 mcp98242 appendix a: revision history revision d (october 2010) the following is the list of modifications: 1. added the udfn package. revision c (july 2009) the following is the list of modifications: 1. updated the dfn/tdfn package throughout document. 2. updated ta b l e 5 - 1 and tab l e 5 - 6 . 3. updated register 5-3, register 5-5, register 5- 7 and register 5-8. 4. updated section 5.1.6 ?device id and revision register? . 5. added section 5.2.3.2 ?interrupt mode? . 6. updated figure 5-9 . 7. section 7.0 ?packaging information? : updated package outline drawings. revision b (february 2008) the following is the list of modifications: 1. added tdfn package throughout document. revision a (september 2006) ? original release of this document. mcp98242 ds21996d-page 52 ? 2010 microchip technology inc. notes: ? 2010 microchip technology inc. ds21996d-page 53 mcp98242 product identification system to order or obtain information, e. g., on pricing or delivery, refer to the factory or the listed sales office . device: mcp98242: digital temperature sensor mcp98242t: digital temperature sensor (tape and reel) grade: b = 1c (max.) from +75c to +95c, b 2c (max.) from +40c to +125c, and b 3c (max.) from -20c to +125c temperature range: e = -40c to +125c package: mc = dual flat no lead (2x3 mm body), 8-lead, mcbac (1) = dual flat no lead (2x3 mm body), 8-lead, muy (2) = dual flat no lead (2x3 mm body), 8-lead, mny (2) = dual flat no lead (2x3 mm body), 8-lead, mnybac (1,2) = dual flat no lead (2x3 mm body), 8-lead, st = plastic thin shrink small outline (4x4 mm body), 8-lead part no. x /xxx package temperature range device examples: a) mcp98242-be/mc: extended temp., 8ld dfn pkg. b) mcp98242t-be/mc: tape and reel, extended temp., 8ld dfn pkg. c) mcp98242-be/st: extended temp., 8ld tssop pkg. d) mcp98242t-be/st: tape and reel, extended temp., 8ld tssop pkg. e) mcp98242-be/mny: extended temp., 8ld tdfn (nickel palladium gold) pkg. f) mcp98242-be/muy: extended temp., 8ld udfn (nickel palladium gold) pkg. ?x grade note 1: ?y? is nickel palladium gold manufacturing designator. only available on the tdfn and udfn packages for this family of products. 2: ?bac? is a non-standard reel manufacturing designator. it designates parts in 8 mm wide by 4 mm wide pitch (tape and reel) on a 13 inch reel with 11k base quantity. mcp98242 ds21996d-page 54 ? 2010 microchip technology inc. notes: ? 2010 microchip technology inc. ds21996d-page 55 information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. it is your responsibility to ensure that your application meets with your specifications. microchip makes no representations or warranties of any kind whether express or implied, written or oral, statutory or otherwise, related to the information, including but not limited to its condition, quality, performance, merchantability or fitness for purpose . microchip disclaims all liability arising from this information and its use. use of microchip devices in life support and/or safety applications is entirely at the buyer?s risk, and the buyer agrees to defend, indemnify and hold harmless microchip from any and all damages, claims, suits, or expenses resulting from such use. no licenses are conveyed, implicitly or otherwise, under any microchip intellectual property rights. trademarks the microchip name and logo, the microchip logo, dspic, k ee l oq , k ee l oq logo, mplab, pic, picmicro, picstart, pic 32 logo, rfpic and uni/o are registered trademarks of microchip technology incorporated in the u.s.a. and other countries. filterlab, hampshire, hi-tech c, linear active thermistor, mxdev, mxlab, seeval and the embedded control solutions company are registered trademarks of microchip technology incorporated in the u.s.a. analog-for-the-digital age, appl ication maestro, codeguard, dspicdem, dspicdem.net, dspicworks, dsspeak, ecan, economonitor, fansense, hi-tide, in-circuit serial programming, icsp, mindi, miwi, mpasm, mplab certified logo, mplib, mplink, mtouch, omniscient code generation, picc, picc-18, picdem, picdem.net, pickit, pictail, real ice, rflab, select mode, total endurance, tsharc, uniwindriver, wiperlock and zena are trademarks of microchip tec hnology incorporated in the u.s.a. and other countries. sqtp is a service mark of microchip technology incorporated in the u.s.a. all other trademarks mentioned herein are property of their respective companies. ? 2010, microchip technology incorporated, printed in the u.s.a., all rights reserved. printed on recycled paper. isbn: 978-1-60932-688-3 note the following details of the code protection feature on microchip devices: ? microchip products meet the specification cont ained in their particular microchip data sheet. ? microchip believes that its family of products is one of the most secure families of its kind on the market today, when used i n the intended manner and under normal conditions. ? there are dishonest and possibly illegal methods used to breach the code protection feature. all of these methods, to our knowledge, require using the microchip produc ts in a manner outside the operating specif ications contained in microchip?s data sheets. most likely, the person doing so is engaged in theft of intellectual property. ? microchip is willing to work with the customer who is concerned about the integrity of their code. ? neither microchip nor any other semiconduc tor manufacturer can guarantee the security of their code. code protection does not mean that we are guaranteeing the product as ?unbreakable.? code protection is constantly evolving. we at microchip are co mmitted to continuously improvin g the code protection features of our products. attempts to break microchip?s code protection feature may be a violation of the digital millennium copyright act. if such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that act. microchip received iso/ts-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona; gresham, oregon and design centers in california and india. the company?s quality system processes and procedures are for its pic ? mcus and dspic ? dscs, k ee l oq ? code hopping devices, serial eeproms, microperipherals, nonvolatile memory and analog products. in addition, microchip?s quality system for the design and manufacture of development systems is iso 9001:2000 certified. ds21996d-page 56 ? 2010 microchip technology inc. americas corporate office 2355 west chandler blvd. chandler, az 85224-6199 tel: 480-792-7200 fax: 480-792-7277 technical support: http://support.microchip.com web address: www.microchip.com atlanta duluth, ga tel: 678-957-9614 fax: 678-957-1455 boston westborough, ma tel: 774-760-0087 fax: 774-760-0088 chicago itasca, il tel: 630-285-0071 fax: 630-285-0075 cleveland independence, oh tel: 216-447-0464 fax: 216-447-0643 dallas addison, tx tel: 972-818-7423 fax: 972-818-2924 detroit farmington hills, mi tel: 248-538-2250 fax: 248-538-2260 kokomo kokomo, in tel: 765-864-8360 fax: 765-864-8387 los angeles mission viejo, ca tel: 949-462-9523 fax: 949-462-9608 santa clara santa clara, ca tel: 408-961-6444 fax: 408-961-6445 toronto mississauga, ontario, canada tel: 905-673-0699 fax: 905-673-6509 asia/pacific asia pacific office suites 3707-14, 37th floor tower 6, the gateway harbour city, kowloon hong kong tel: 852-2401-1200 fax: 852-2401-3431 australia - sydney tel: 61-2-9868-6733 fax: 61-2-9868-6755 china - beijing tel: 86-10-8528-2100 fax: 86-10-8528-2104 china - chengdu tel: 86-28-8665-5511 fax: 86-28-8665-7889 china - chongqing tel: 86-23-8980-9588 fax: 86-23-8980-9500 china - hong kong sar tel: 852-2401-1200 fax: 852-2401-3431 china - nanjing tel: 86-25-8473-2460 fax: 86-25-8473-2470 china - qingdao tel: 86-532-8502-7355 fax: 86-532-8502-7205 china - shanghai tel: 86-21-5407-5533 fax: 86-21-5407-5066 china - shenyang tel: 86-24-2334-2829 fax: 86-24-2334-2393 china - shenzhen tel: 86-755-8203-2660 fax: 86-755-8203-1760 china - wuhan tel: 86-27-5980-5300 fax: 86-27-5980-5118 china - xian tel: 86-29-8833-7252 fax: 86-29-8833-7256 china - xiamen tel: 86-592-2388138 fax: 86-592-2388130 china - zhuhai tel: 86-756-3210040 fax: 86-756-3210049 asia/pacific india - bangalore tel: 91-80-3090-4444 fax: 91-80-3090-4123 india - new delhi tel: 91-11-4160-8631 fax: 91-11-4160-8632 india - pune tel: 91-20-2566-1512 fax: 91-20-2566-1513 japan - yokohama tel: 81-45-471- 6166 fax: 81-45-471-6122 korea - daegu tel: 82-53-744-4301 fax: 82-53-744-4302 korea - seoul tel: 82-2-554-7200 fax: 82-2-558-5932 or 82-2-558-5934 malaysia - kuala lumpur tel: 60-3-6201-9857 fax: 60-3-6201-9859 malaysia - penang tel: 60-4-227-8870 fax: 60-4-227-4068 philippines - manila tel: 63-2-634-9065 fax: 63-2-634-9069 singapore tel: 65-6334-8870 fax: 65-6334-8850 taiwan - hsin chu tel: 886-3-6578-300 fax: 886-3-6578-370 taiwan - kaohsiung tel: 886-7-213-7830 fax: 886-7-330-9305 taiwan - taipei tel: 886-2-2500-6610 fax: 886-2-2508-0102 thailand - bangkok tel: 66-2-694-1351 fax: 66-2-694-1350 europe austria - wels tel: 43-7242-2244-39 fax: 43-7242-2244-393 denmark - copenhagen tel: 45-4450-2828 fax: 45-4485-2829 france - paris tel: 33-1-69-53-63-20 fax: 33-1-69-30-90-79 germany - munich tel: 49-89-627-144-0 fax: 49-89-627-144-44 italy - milan tel: 39-0331-742611 fax: 39-0331-466781 netherlands - drunen tel: 31-416-690399 fax: 31-416-690340 spain - madrid tel: 34-91-708-08-90 fax: 34-91-708-08-91 uk - wokingham tel: 44-118-921-5869 fax: 44-118-921-5820 worldwide sales and service 08/04/10 |
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