MCP98243 Memory Module Temperature Sensor w/ EEPROM for SPD Features Description • • • • • Microchip Technology Inc.’s MCP98243 digital temperature sensor converts temperature from -40°C and +125°C to a digital word. This sensor meets JEDEC Specification JC42.4-TSE2002B3 Platform Memory Module Thermal Sensor Component. It provides an accuracy of ±0.2°C/±1°C (typical/ maximum) from +75°C to +95°C. In addition, this device has an internal 256 Byte EEPROM which can be used to store memory module and vendor information. Meets JEDEC Specification JC42.4-TSE2002B3 Temperature Sensor + 2 Kbit Serial EEPROM EEPROM for Serial Presence Detect (SPD) 2-wire I2C™/SMBus Interface Available Packages: - DFN-8, TDFN-8, UDFN-8, TSSOP-8 Temperature Sensor Features • Temperature-to-Digital Converter • Sensor Accuracy (Grade B): - ±0.2°C/±1°C (typ./max.) → +75°C to +95°C - ±0.5°C/±2°C (typ./max.) → +40°C to +125°C - ±1°C/±3°C (typ./max.) → -20°C to +125°C • Specified VDD Range: 3.0V to 3.6V • Operating Current: 200 µA (typical) • Operating VDD Range: 2.7V to 5.5V Serial EEPROM Features • Specified VDD Range: 1.8V to 5.5V • Operating Current: - Write → 1.1 mA (typical) for 3.5 ms (typical) - Read → 100 µA (typical) • Permanent and Reversible Software Write Protect • Software Write Protection for the lower 1 Kbit • Organized as 1 block of 256 x 8-bit (2 Kbit) Typical Applications • DIMM Modules for Servers, PCs, and Laptops • General Purpose Temperature Datalog DIMM MODULE The MCP98243 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 boundaries. When the temperature changes beyond the specified Event boundary limits, the MCP98243 outputs an Alert signal at the Event pin. The user has the option of setting the temperature 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 EEPROM is designed specifically for DRAM DIMMs (Dual In-line Memory Modules) Serial Presence Detect (SPD). The lower 128 Bytes (address 0x00 to 0x7F) 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 0x80 to 0xFF) can be used for general purpose data storage. These addresses are not write protected. This sensor has an industry standard 2-wire, I2C compatible serial interface, allowing up to eight devices to be controlled in a single serial bus. Package Types 8-Pin 2x3 DFN/TDFN/UDFN * A0 1 A1 2 A2 3 GND 4 EP 9 8-Pin TSSOP 8 VDD A0 1 8 VDD 7 Event A1 2 7 Event 6 SCL A2 3 6 SCL 5 SDA GND 4 5 SDA * Includes Exposed Thermal Pad (EP); see Table 3-1. MCP98243 © 2009 Microchip Technology Inc. DS22153B-page 1 MCP98243 Sensor Typical Accuracy Performance 50% TA = +85°C 1,063,478 units 63 Production lots Occurrences 40% Statistics: Average = 0.003 °C St. Dev = 0.13 °C ±3 Sigma = ±0.4 °C 30% 20% 10% 1.0 0.8 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 -0.8 -1.0 0% Temperature Accuracy (°C) Note: This accuracy data from the production system represents the typical accuracy performance of the MCP98242 Memory Module Temperature Sensor. The MCP98242 production methodology is also used for the MCP98243 to achieve the same typical accuracy performance. MCP98243 VS. MCP98242 Feature Event Output in Shutdown Mode I2C communication Timeout Range I2C Maximum Bus Frequency 2C I SCL & SDA VIL/VIH voltage levels VHV A0 range 2 I C Spike Supression I2C input hysteresis Device/Revision ID Register DS22153B-page 2 MCP98243 MCP98242 Event Output De-asserts Event Output Remains Asserted tOUT = 25 ms to 35 ms tOUT = 20 ms to 35 ms 400 kHz 100 kHz VIL_MAX=0.3*VDD, VIH_MIN=0.7*VDD VIL_MAX = 0.8V, VIH_MIN = 2.1V 7V to 12V 8V to 12V 50 ns — 0.05VDD 0.5V 0x2101 (hex) 0x2001 © 2009 Microchip Technology Inc. MCP98243 1.0 ELECTRICAL CHARACTERISTICS †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 specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings † VDD.................................................................................. 6.0V Voltage at all Input/Output pins ............... GND – 0.3V to 6.0V Pin A0 ................................................... GND – 0.3V to 12.5V Storage temperature .....................................-65°C to +150°C Ambient temp. with power applied ................-40°C to +125°C Junction Temperature (TJ) .......................................... +150°C ESD protection on all pins (HBM:MM) ................. (4 kV:300V) Latch-Up Current at each pin (25°C) ....................... ±200 mA TEMPERATURE SENSOR DC CHARACTERISTICS Electrical Specifications: Unless otherwise indicated, VDD = 3.0V to 3.6V, GND = Ground, and TA = -20°C to +125°C. Parameters Sym Min Typ Max Unit Conditions TACY -1.0 ±0.2 +1.0 °C +40°C < TA ≤ +125°C -2.0 ±0.5 +2.0 °C -20°C < TA ≤ +125°C -3.0 ±1 +3.0 °C — -1 — °C tCONV — 65 125 ms Specified Voltage Range VDD 3.0 — 3.6 V JC42.4 Specified Voltage Range Operating Voltage Range VDD 2.7 — 5.5 V Note 1 Operating Current IDD_TS — 200 500 µA EEPROM Inactive Shutdown Current ISHDN — 1 3 µA EEPROM Inactive, I2C Bus Inactive Power On Reset (POR) VPOR_TS — 2.2 — V Power Supply Rejection, Δ°C/ΔVDD — ±0.3 — °C/V — ±0.15 — °C Temperature Sensor Accuracy +75°C < TA ≤ +95°C TA = -40°C JC42.4 - TSE2002B3 Grade B Accuracy Specification Temperature Conversion Time 0.25°C/bit 15 s/sec (typical) (See Section 5.2.4) Power Supply TA = +25°C Threshold for falling VDD voltage VDD = 2.7V to 5.5V VDD = 3.3V+150 mVPP AC (0 to 1 MHz) Event Output (Open-Drain output, external pull-up or pull-down resistor required), see Section 5.2.3 High-level Current (leakage) IOH — — 1 Low-level Voltage VOL µA VOH = VDD (Active-Low, Pull-up Resistor) — — 0.4 V IOL= 3 mA (Active-Low, Pull-up Resistor) Low-level Current (leakage) IOL — — 1 µA VOL = VSS (Active-High, Pull-down Resistor) High-level Voltage VOH — — VDD-0.5 V IOH= 3 mA (Active-High, Pull-down Resistor) Time to 63% (89°C) Thermal Response, from +25°C (Air) to +125°C (oil bath) DFN/UDFN/TDFN-8 TSSOP-8 Note 1: tRES — 0.7 — s — 1.4 — s Characterized but not production tested. Also, see Section 2.0 “Typical Performance Curves”. © 2009 Microchip Technology Inc. DS22153B-page 3 MCP98243 EEPROM DC CHARACTERISTICS Electrical Specifications: Unless otherwise indicated, VDD = 1.8V to 5.5V, GND = Ground, and TA = -20°C to +125°C. Parameters Sym Min Typ Max Unit Conditions Operating Voltage Range VDD 1.8 — 5.5 V Current, EEPROM write IDD_EE — 1100 2000 µA Sensor in Shutdown Mode (for tWC), (Note 1) Current, EEPROM read IDD_EE — 100 500 µA Sensor in Shutdown Mode (Note 1) Power On Reset (POR) VPOR_EE — 1.6 — V EEPROM tWC — 3 5 — — 1M — Power Supply Write Cycle time (byte/page) Endurance TA = +25°C ms cycles Number of Write Cycles, VDD = 5V (Note 2) EEPROM Write Temperature EEWRITE 0 — 85 °C EEPROM Read Temperature EEREAD -40 — 125 °C 7 — 12 V — VDD — V Write Protect Voltage SWP and CWP Voltage VHV PWP Voltage Note 1: 2: 3: Applied at A0 pin (Note 3) For VDD ranges of 1.8V to the temperature sensor VPOR_TS, the temperature sensor becomes partially biased and consumes 80 µA (typical) until the sensor POR resets and acknowledges a shutdown command. See Figure 2-15. Characterized but not production tested. For endurance estimates in a specific application, please consult the Total Endurance™ Model which can be obtained from Microchip’s web site at www.microchip.com. The range of voltage applied at A0 pin for Permanent Write Protect is GND to VDD + 1V. See Figure 2-13 and Section 5.3.3 “Write Protection”. INPUT/OUTPUT PIN DC CHARACTERISTICS (NOTE 1) Electrical Specifications: Unless otherwise indicated, VDD = 1.8V to 5.5V, GND = Ground and TA = -20°C to +125°C. Parameters Sym Min Typ Max Units V Conditions Serial Input/Output (SCL, SDA, A0, A1, A2) (Note 2) Input High-level Voltage VIH 0.7VDD — — Low-level Voltage VIL — — 0.3VDD V Input Current IIN — — ±5 µA SDA and SCL only Input Impedance (A0, A1, A2) ZIN — 1 — MΩ VIN > VIH Input Impedance (A0, A1, A2) ZIN — 200 — kΩ VIN < VIL Low-level Voltage VOL — — 0.4 V IOL= 3 mA High-level Current (leakage) IOH — — 1 µA VOH = VDD Low-level Current IOL 6 — — mA VOL = 0.6V CIN — 5 — pF VHYST — 0.05VDD — V VDD > 2V — 0.1VDD — V VDD < 2V — — 50 ns Output (SDA only) Capacitance SDA and SCL Inputs Hysteresis Spike Supression Note 1: 2: TSP These specifications apply for the Temperature Sensor and EEPROM. For VDD ranges of 1.8V to the temperature sensor VPOR_TS, the temperature sensor becomes partially biased and consumes 80 µA (typical) until the sensor POR resets and acknowledges a shutdown command. See Figure 2-15. DS22153B-page 4 © 2009 Microchip Technology Inc. MCP98243 SENSOR AND EEPROM SERIAL INTERFACE TIMING SPECIFICATIONS Electrical Specifications: Unless otherwise indicated, GND = Ground, TA = -20°C to +125°C, and CL = 80 pF (Note 1, 5). VDD= 1.8V to 5.5V VDD= 2.2V to 5.5V Parameters Sym Min Max Min Max Units Conditions 2 2-Wire I C Interface Serial port frequency fSCL 10 100 10 400 kHz Low Clock tLOW 4700 — 1300 — ns Note 2 High Clock tHIGH 4000 — 600 — ns Note 2 tR — 1000 20 300 ns tF 20 300 20 300 ns tSU:DI 250 — 100 — ns Note 3 Rise time Fall time Data in Setup time Note 2, 4 Data in Hold time tHD:DI 0 — 0 — ns Note 6 Data out Hold time tHD:DO 200 900 200 900 ns Note 4 Start Condition Setup time tSU:STA 4700 — 600 — ns Start Condition Hold time tHD:STA 4000 — 600 — ns Stop Condition Setup time tSU:STO 4000 — 600 — ns Bus idle tB:FREE 4700 — 1300 — ns tOUT — — 25 35 ms Cb — — — 400 pf Time out (Sensor Only) Bus Capacitive load Note 1: 2: 3: 4: 5: 6: VDD= 3.0V to 3.6V All values referred to VIL MAX and VIH MIN levels. If tLOW > tOUT or tHIGH > tOUT, the temperature sensor I2C interface will time out. A Repeat Start command is required for communication. This device can be used in a Standard-mode I2C-bus system, but the requirement tSU:DAT ≥ 250 ns must be met. This device does not stretch SCL Low time. It outputs the next data bit to the SDA line within tR MAX + tSU:DI MIN = 1000 ns + 250 ns = 1250 ns (according to the Standard-mode I2C-bus specification) before the SCL line is released. As a transmitter, the device provides internal minimum delay time tHD:DAT MIN to bridge the undefined region (min. 300 ns) of the falling edge of SCL tF MAX to avoid unintended generation of Start or Stop conditions. For VDD ranges of 1.8V to the temperature sensor VPOR_TS, the temperature sensor becomes partially biased and consumes 100 µA (typical) until the sensor POR resets and acknowledges a shutdown command. As a receiver, SDA should not be sampled at the falling edge of SCL. SDA can transition tHD:DI 0 ns after SCL toggles Low. © 2009 Microchip Technology Inc. DS22153B-page 5 MCP98243 TEMPERATURE CHARACTERISTICS Electrical Specifications: Unless otherwise indicated, VDD = 1.8V to 5.5V for the EEPROM, VDD = 3.0V to 3.6V for the Temperature Sensor, and GND = Ground. Parameters Sym Min Typ Max Units Specified Temperature Range TA -20 — +125 °C Operating Temperature Range TA -40 — +125 °C Storage Temperature Range TA -65 — +150 °C Thermal Resistance, 8L-DFN θJA — 68 — °C/W Thermal Resistance, 8L-TDFN θJA — 52.5 — °C/W Thermal Resistance, 8L-TSSOP θJA — 139 — °C/W Thermal Resistance, 8L-UDFN θJA — 41 — °C/W Conditions Temperature Ranges Note 1 Thermal Package Resistances Note 1: Operation in this range must not cause TJ to exceed Maximum Junction Temperature (+150°C). U :S T tB O :F R EE tS O W tH D :D I /t tS U :D I H D :D O tO U T tR ,t F SD A SC L tL tH tS IG H U :S T tS O U :D I TIMING DIAGRAM Data Transmission Start Condition Stop Condition GRAPHICAL SYMBOL DESCRIPTION Voltage VDD INPUT Voltage VIH OUTPUT VDD VOL VIL IOL Current Current IIN IOH time DS22153B-page 6 time © 2009 Microchip Technology Inc. MCP98243 2.0 TYPICAL PERFORMANCE CURVES 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. Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD, and TA = -40°C to +125°C. 10000 VDD= 3.3V 2.0 1000 1.0 Spec. Limits IDD (µA) Temperature Accuracy (°C) 3.0 0.0 EEPROM Write (Sensor in Shutdown Mode) 100 10 -2.0 EEPROM Read (Sensor in Shutdown Mode) 1 -3.0 -40 -20 0 20 FIGURE 2-1: Accuracy. 40 60 TA (°C) 80 100 -40 120 Average Temperature 60% 50% -20 0 FIGURE 2-4: Temperature. 70% 20 40 60 TA (°C) 80 100 120 Supply Current vs. 35 TA = +95°C VDD = 3.3V 221 units VDD = 3.3V to 3.6V 40% tOUT (ms) Occurrences Sensor (EEPROM Inactive) -1.0 30% 20% 30 10% 25 1.00 0.75 0.50 0.25 0.00 -0.25 -0.50 -0.75 -1.00 0% -40 -20 0 20 Temperature Accuracy (°C) FIGURE 2-2: Temperature Accuracy Histogram, TA = +95°C. FIGURE 2-5: Temperature. 70% 40% 30% 120 Serial Bus Time-Out vs. 2 1.5 1.00 0.75 0 0.50 0% 0.25 0.5 0.00 10% -0.25 1 -0.50 20% -0.75 100 VPOR_TS 2.5 VPOR (V) 50% 80 3 TA = +75°C VDD = 3.3V 221 units -1.00 Occurrences 60% 40 60 TA (°C) Temperature Accuracy (°C) FIGURE 2-3: Temperature Accuracy Histogram, TA = +75°C. © 2009 Microchip Technology Inc. VPOR_EE -40 -20 0 20 40 60 TA (°C) 80 100 120 FIGURE 2-6: Power-on Reset Threshold Voltage vs. Temperature. DS22153B-page 7 MCP98243 Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD, and TA = -40°C to +125°C. 48 IOH = IOL = 3 mA 0.3 0.2 SDA VOL 0.1 30 24 18 6 -40 -20 0 FIGURE 2-7: Temperature. 20 40 60 TA (°C) 80 -40 100 120 Event and SDA VOL vs. -20 0 FIGURE 2-10: 20 40 60 TA (°C) 80 100 120 SDA IOL vs. Temperature. 3.0 Temperature Accuracy (°C) 125 110 tCONV (ms) 36 12 Event VOL 0 95 80 65 50 35 Δ°C/ΔVDD = 0.4°C/V 2.0 VDD = 2.7V VDD = 3.0V VDD = 3.6V VDD = 5.5V 1.0 0.0 -1.0 -2.0 -3.0 -40 -20 0 FIGURE 2-8: Temperature. 1.0 20 40 60 TA (°C) 80 100 120 0.0 -0.5 No decoupling capacitor 100 100 1k 1k 1,000 10k 10k 10,000 100k 100k 100,000 1M 1M 1,000,000 DS22153B-page 8 Power Supply Rejection vs. 20 40 60 TA (°C) 80 100 120 Temperature Accuracy vs. 100% 80% 60% TSSOP-8 DFN-8 40% 20% 22°C (Air) to 125°C (Oil bath) 0% -2 0 Frequency (Hz) FIGURE 2-9: Frequency. 0 120% TA = 25°C Δ°C/ΔVDD, VDD = 3.3V + 150 mVPP (AC) -20 FIGURE 2-11: VDD. Conversion Rate vs. 0.5 -1.0 -40 Thermal Response (%) Normalized Temp. Error (°C) VOL = 0.6V 42 Event (VDD - VOH) SDA IOL (mA) SDA and Event Output (V) 0.4 FIGURE 2-12: Response. 2 4 6 8 Time (s) 10 12 14 16 Package Thermal © 2009 Microchip Technology Inc. MCP98243 Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD, and TA = -40°C to +125°C. 12 Minimum SWP/CWP Voltage 6 4 Maximum PWP Voltage (VDD + 1V) 2 VPOR_TS, Sensor in Shutdown Mode 80 ISHDN (µA) VHV (V) 8 100 VHV applied at A0 pin. See Table 5-4 for Pins A1 and A2 connection No SWP/CWP/PWP function within this range 10 60 TA = -40°C TA = +25°C TA = +85°C TA = +125°C 40 20 0 0 1.5 2.0 2.5 FIGURE 2-13: Voltage Range. 3.0 3.5 4.0 VDD (V) 4.5 5.0 5.5 SWP/CWP/PWP High 1.5 2.0 FIGURE 2-15: 2.5 3.0 3.5 4.0 VDD (V) 4.5 5.0 5.5 Shutdown Current vs. VDD. 3.00 ISHDN (µA) 2.50 2.00 1.50 1.00 0.50 0.00 -40 -20 FIGURE 2-14: Temperature. 0 20 40 60 TA (°C ) 80 100 120 Shutdown Current vs. © 2009 Microchip Technology Inc. DS22153B-page 9 MCP98243 NOTES: DS22153B-page 10 © 2009 Microchip Technology Inc. MCP98243 3.0 PIN DESCRIPTION The descriptions of the pins are listed in Table 3-1. TABLE 3-1: PIN FUNCTION TABLES MCP98243 Symbol Description 1 A0 Slave Address and EEPROM Software Write Protect high voltage input (VHV) 2 2 A1 Slave Address 3 3 A2 Slave Address 4 4 GND Ground 5 5 SDA Serial Data Line 6 6 SCL Serial Clock Line 7 7 Event 8 8 VDD Power Pin 9 — EP Exposed Thermal Pad (EP); must be connected to GND. DFN, TDFN, UDFN TSSOP 1 3.1 Temperature Alert Output Address Pins (A0, A1, A2) 3.4 These pins are device address input pins. Serial Clock Line (SCL) 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. The SCL 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”). TABLE 3-2: 3.5 Device MCP98243 ADDRESS BYTE Address Code A6 A5 A4 A3 Sensor 0 0 1 1 EEPROM 1 0 1 0 EEPROM Write Protect 0 1 1 0 Note: Slave Address A2 A1 A0 X X X User-selectable address is shown by X. The A0 Address pin is a multi-function pin. This input pin is also used for high voltge input VHV to enable the EEPROM Software Write Protect feature, see Section 5.3.3 “Write Protection”. All address pin have an internal pull-down resistors. 3.2 Ground Pin (GND) The GND pin is the system ground pin. 3.3 Temperature Alert, Open-Drain Output (Event) The MCP98243 temperature Event output 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 (VDD) VDD 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 can be connected to the same potential on the Printed Circuit Board (PCB). This provides better thermal conduction from the PCB to the die. 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”). © 2009 Microchip Technology Inc. DS22153B-page 11 MCP98243 NOTES: DS22153B-page 12 © 2009 Microchip Technology Inc. MCP98243 4.0 SERIAL COMMUNICATION 4.1 2-Wire Standard Mode I2C™ Protocol-Compatible Interface The MCP98243 serial clock input (SCL) and the bidirectional serial data line (SDA) form a 2-wire bidirectional Standard mode I2C compatible communication port (refer to the Input/Output Pin DC Characteristics (Note 1) Table and Sensor And EEPROM Serial Interface Timing Specifications Table). The following bus protocol has been defined: TABLE 4-1: Term MCP98243 SERIAL BUS PROTOCOL DESCRIPTIONS Description Master The device that controls the serial bus, typically a microcontroller. Slave The device addressed by the master, such as the MCP98243. 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 MCP98243 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 SCL remain high. Data Valid SDA must remain stable before SCL becomes high in order for a data bit to be considered valid. During normal data transfers, SDA only changes state while SCL is low. 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 tB-FREE. © 2009 Microchip Technology Inc. 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 MCP98243 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 MCP98243 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 SCL is high) is the Start condition. All data transfers must be preceded by a Start condition from the master. A lowto-high transition of the SDA line (while SCL is high) signifies a Stop condition. If a Start or Stop condition is introduced during data transmission, the MCP98243 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 MCP98243. The address for the MCP98243 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 VDD ‘1’ or GND ‘0’. The 7-bit address transmitted in the serial bit stream must match the selected address for the MCP98243 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). Address Byte 1 2 SCL 0 SDA 0 3 4 5 6 7 8 A C K 1 1 A2 A1 A0 Start Address Code 9 Slave Address R/W MCP98243 Response FIGURE 4-1: Device Addressing. DS22153B-page 13 MCP98243 4.1.5 DATA VALID After the Start condition, each bit of data in transmission needs to be settled for a time specified by tSU-DATA before SCL toggles from low-to-high (see “Sensor And EEPROM Serial Interface Timing Specifications” on Page 5). 4.1.6 ACKNOWLEDGE (ACK/NAK) 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. 4.1.7 TIME OUT (MCP98243, SENSOR ONLY) If the SCL stays low or high for time specified by tOUT, the MCP98243 temperature sensor resets the serial interface. This dictates the minimum clock speed as specified in the specification. However, the EEPROM does not reset the serial interface. Therefore, the master can hold the clock indefinitely to process data from the EEPROM. The acknowledging device pulls down the SDA line for tSU-DATA before the low-to-high transition of SCL from the master. SDA also needs to remain pulled down for tH-DATA after a high-to-low transition of SCL. 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. DS22153B-page 14 © 2009 Microchip Technology Inc. MCP98243 5.0 mable registers and a 2-wire I2C protocol compatible serial interface. Figure 5-1 shows a block diagram of the register structure. FUNCTIONAL DESCRIPTION The MCP98243 temperature sensors consists of a band-gap type temperature sensor, a Delta-Sigma Analog-to-Digital Converter (ΣΔ ADC), user-program- Temperature Sensor EEPROM Hysteresis Shutdown Critical Trip Lock HV Generator Alarm Win. Lock Bit Clear Event Event Status Output Control Write Protected Array (00h-7Fh) Critical Event only Event Polarity Event Comp/Int Band-Gap Temperature Sensor Address Decoder X Configuration Temperature ΣΔ ADC Standard Array (80h-FFh) TUPPER TLOWER TCRIT Manufacturer ID Device ID/Rev 0.5°C/bit 0.25°C/bit 0.125°C/bit 0.0625°C/bit Memory Control Logic Resolution Write Protect Circuitry Capability Shutdown Status I2C Bus Time-out Address Decoder Y Accepts VHV Selected Resolution Sense Amp R/W Control Temp. Range Accuracy Output Feature Register Pointer Standard I2C Interface A0 A1 FIGURE 5-1: A2 Event SDA SCL VDD GND Functional Block Diagram. © 2009 Microchip Technology Inc. DS22153B-page 15 MCP98243 5.1 Registers The MCP98243 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 tCONV. The Event Temperature Upper-Boundary and Lower-Boundary Trip registers are read/writes. If the ambient temperature drifts beyond the user-specified limits, the MCP98243 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. REGISTER 5-1: The Capability register is used to provide bits describing the MCP98243’s capability in measurement resolution, measurement range and device accuracy. The device Configuration register provides access to configure the MCP98243’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 MCP98243 using the serial interface. This is an 8-bit write-only pointer. However, the four Least Significant bits are used as pointers and all unused bits (bits 7-4) need to be cleared or set to ‘0’. Register 5-1 describes the pointer or the address of each register. 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’’ bit 3-0 Pointer Bits: 0000 = Capability register 0001 = Configuration register (CONFIG) 0010 = Event Temperature Upper-Boundary Trip register (TUPPER) 0011 = Event Temperature Lower-Boundary Trip register (TLOWER) 0100 = Critical Temperature Trip register (TCRIT) 0101 = Temperature register (TA) 0110 = Manufacturer ID register 0111 = Device ID/Revision register 1000 = Resolution register 1XXX = Reserved (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.) DS22153B-page 16 © 2009 Microchip Technology Inc. MCP98243 TABLE 5-1: BIT ASSIGNMENT SUMMARY FOR ALL TEMPERATURE SENSOR REGISTERS (SEE SECTION 5.4) Bit Assignment Register Pointer (Hex) MSB/ LSB 0x00 MSB 0 LSB SHDN Status 0x01 7 6 5 4 3 0 0 0 0 tOUT Range VHV Resolution MSB 0 0 0 0 0 LSB Crt Loc Win Loc Int Clr Evt Stat Evt Cnt 2 1 0 0 0 0 Range Accuracy Event Hysteresis SHDN Evt Sel Evt Pol Evt Mod 24°C MSB 0 0 0 SIGN 27°C 26°C 25°C LSB 23°C 22°C 21°C 20°C 2-1°C 2-2°C 0 0 0x03 MSB 0 0 0 SIGN 27°C 26°C 25°C 24°C LSB 23°C 22°C 21°C 20°C 2-1°C 2-2°C 0 0 0x04 MSB 0 0 0 SIGN 27°C 26°C 25°C 24°C LSB 23°C 22°C 21°C 20°C 2-1°C 2-2°C 0 0 0x05 MSB TA ≥ TCRIT TA < TLOWER SIGN 27°C 26°C 25°C 24°C LSB 23°C TA > TUPPER 21°C 20°C 2-1°C 2-2°C 2-3°C 2-4°C 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 1 LSB 0 0 0 0 0 0 0 1 0x08 LSB 0 0 0 0 0 0 0 1 0x02 © 2009 Microchip Technology Inc. 22°C DS22153B-page 17 MCP98243 5.1.1 CAPABILITY REGISTER This is a read-only register used to identify the temperature sensor capability. In this case, the MCP98243 is capable of providing temperature at 0.25°C resolution, measuring temperature below and above 0°C, providing ±1°C and ±2°C 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 R-1 R-1 R-1 SHDN Status tOUT Range VHV R-0 R-1 Resolution R-1 R-1 R-1 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 15-8 Unimplemented: Read as ‘0’ bit 7 Event output status during Shutdown (SHDN Status): 0 = Event output remains asserted during shutdown 1 = Event output de-asserts during shutdown. After shutdown it takes tCONV to re-assert the Event output (power-up default) bit 6 I2C Bus time-out (tOUT Range): 0 = Bus time-out range is 10 ms to 60 ms 1 = Bus time-out range is 25 ms to 35 ms (power-up default) bit 5 High Voltage Input 0 = Pin A0 does not accept High Voltage 1 = Pin A0 accepts High Voltage for the internal EEPROM Write Protect feature (power-up default) bit 4-3 Resolution: 00 = 0.5°C 01 = 0.25°C (power up default) 10 = 0.125°C 11 = 0.0625°C These bits reflect the selected resolution (see Section 5.2.4 “Temperature Resolution”) bit 2 Temperature Measurement Range (Meas. Range): 0 = TA = 0 (decimal) for temperature below 0°C 1 = The part can measure temperature below 0°C (power-up default) DS22153B-page 18 © 2009 Microchip Technology Inc. MCP98243 CAPABILITY REGISTER (READ-ONLY) → ADDRESS ‘0000 0000’b (CONTINUED) REGISTER 5-2: bit 1 Accuracy: 0 = Accuracy → ±2°C from +75°C to +95°C (Active Range) and ±3°C from +40°C to +125°C (Monitor Range) 1 = Accuracy → ±1°C from +75°C to +95°C (Active Range) and ±2°C from +40°C to +125°C (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 (TUPPER/TLOWER/TCRIT registers) and a temperautre event output (JC 42.4 required feature) 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 W C K 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 0 SCL SDA S A Address Byte A C K Capability Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 R C 0 0 0 0 0 0 0 0 1 2 3 4 5 6 7 8 0 0 0 0 1 1 1 1 SCL SDA S A K A C K MSB Data Address Byte MCP98243 N A P K LSB Data Master Master FIGURE 5-2: Timing Diagram for Reading the Capability Register (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 19 MCP98243 5.1.2 SENSOR CONFIGURATION REGISTER (CONFIG) The MCP98243 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 TUPPER and TLOWER temperature boundary or TCRIT only), read Event output status and set Event output polarity and mode (Comparator Output or Interrupt Output mode). 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 (TA) 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 TUPPER, TLOWER and TCRIT 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”). The temperature hysteresis bits 10 and 9 can be used to prevent output chatter when the ambient temperature gradually changes beyond the userspecified temperature boundary (see Section 5.2.2 “Temperature Hysteresis (THYST)”. The Continuous CONFIGURATION REGISTER (CONFIG) → ADDRESS ‘0000 0001’b REGISTER 5-3: U-0 U-0 U-0 U-0 U-0 — — — — — R/W-0 R/W-0 THYST R/W-0 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 bit 15-11 Unimplemented: Read as ‘0’ bit 10-9 TUPPER and TLOWER Limit Hysteresis (THYST): 00 = 0°C (power-up default) 01 = 1.5°C 10 = 3.0°C 11 = 6.0°C x = Bit is unknown (Refer to Section 5.2.3 “Event Output Configuration”) This bit can not be altered when either of the lock bits are set (bit 6 and bit 7). This bit can be programmed in shutdown mode. 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. Event output will de-assert. 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”). DS22153B-page 20 © 2009 Microchip Technology Inc. MCP98243 REGISTER 5-3: bit 7 CONFIGURATION REGISTER (CONFIG) → ADDRESS ‘0000 0001’b TCRIT Lock Bit (Crit. Lock): 0 = Unlocked. TCRIT register can be written. (power-up default) 1 = Locked. TCRIT register can not be written When enabled, this bit remains set ‘1’ or locked until cleared by internal reset (Section 5.4 “Summary of Power-on Default”). This bit does not require a double-write. This bit can be programmed in shutdown mode. bit 6 TUPPER and TLOWER Window Lock Bit (Win. Lock): 0 = Unlocked. TUPPER and TLOWER registers can be written. (power-up default) 1 = Locked. TUPPER and TLOWER registers can not be written When enabled, this bit remains set ‘1’ or locked until cleared by power-on Respell (Section 5.4 “Summary of Power-on Default”). This bit does not require a double-write. This bit can be programmed in shutdown mode. bit 5 Interrupt Clear (Int. Clear) Bit: 0 = No effect (power-up default) 1 = Clear interrupt output. When read this bit returns ‘0’ This bit clears the Interrupt flag which de-asserts Event output. In shutdown mode, the Event output is always de-asserted. Therefore, setting this bit in shutdown mode clears the interrupt after the device returns to normal operation. 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 In shutdown mode this bit will clear because Event output is always de-asserted in shutdown mode. bit 3 Event Output Control (Event Cnt.) Bit: 0 = Event output Disabled (power-up default) 1 = Event output Enabled This bit can not be altered when either of the lock bits is set (bit 6 and bit 7). This bit can be programmed in shutdown mode, but Event output will remain de-asserted. bit 2 Event Output Select (Event Sel.) Bit: 0 = Event output for TUPPER, TLOWER and TCRIT (power-up default) 1 = TA ≥ TCRIT only. (TUPPER and TLOWER temperature boundaries are disabled.) When the Alarm Window Lock bit is set, this bit cannot be altered until unlocked (bit 6). This bit can be programmed in shutdown mode, but Event output will remain de-asserted. bit 1 Event Output Polarity (Event Pol.) Bit: 0 = Active low (power-up default. Pull-up resistor required) See Section 5.2.3 “Event Output Configuration” 1 = Active-high (Pull-down resistor required) See Section 5.2.3 “Event Output Configuration” This bit cannot be altered when either of the lock bits is set (bit 6 and bit 7). This bit can be programmed in shutdown mode, but Event output will remain de-asserted. 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). This bit can be programmed in shutdown mode, but Event output will remain de-asserted. © 2009 Microchip Technology Inc. DS22153B-page 21 MCP98243 • Writing to the CONFIG Register to Enable the Event Output pin <0000 0000 0000 1000>b. 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 W C 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 1 SCL SDA S A K Address Byte A C K Configuration Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 0 A C K 1 2 3 4 5 6 7 8 0 0 0 0 1 0 0 0 MSB Data A C K P LSB Data MCP98243 MCP98243 Note: this is an example routine: i2c_start(); // send START command i2c_write(AddressByte & 0xFE); //WRITE Command i2c_write(0x01); // Write CONFIG Register i2c_write(0x00); // Write data i2c_write(0x08); // Write data i2c_stop(); // send STOP command //also, make sure bit 0 is cleared ‘0’ FIGURE 5-3: Timing Diagram for Writing to the Configuration Register (See Section 4.0 “Serial Communication”. DS22153B-page 22 © 2009 Microchip Technology Inc. MCP98243 • Reading the CONFIG Register. 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Note: SCL SDA 0 S 0 1 A 2 1 A 1 A A 0 W C K 0 Address Byte 0 0 0 0 0 0 It is not necessary to select the register pointer if it was set from the previous read/write. A C K 1 Configuration Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 R C 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 0 1 2 3 4 5 6 7 8 0 0 0 0 1 0 0 0 SCL SDA S A K Address Byte A C K P LSB Data MSB Data MCP98243 N A K Master Master Note: this is an example routine: i2c_start(); // send START command i2c_write(AddressByte & 0xFE); //WRITE Command //also, make sure bit 0 is cleared ‘0’ i2c_write(0x01); // Write CONFIG Register i2c_start(); // send Repeat START command i2c_write(AddressByte | 0x01); //READ Command //also, make sure bit 0 is set ‘1’ UpperByte = i2c_read(ACK); // READ 8 bits //and Send ACK bit LowerByte = i2c_read(NAK); // READ 8 bits //and Send NAK bit i2c_stop(); // send STOP command FIGURE 5-4: Timing Diagram for Reading from the Configuration Register (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 23 MCP98243 5.1.3 UPPER/LOWER/CRITICAL TEMPERATURE LIMIT REGISTERS (TUPPER/TLOWER/TCRIT) The MCP98243 has a 16-bit read/write Event output Temperature Upper-Boundary Trip register (TUPPER), a 16-bit Lower-Boundary Trip register (TLOWER) and a 16-bit Critical Boundary Trip register (TCRIT) 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 MCP98243 asserts an Event output. (Refer to Section 5.2.3 “Event Output Configuration”). REGISTER 5-4: UPPER/LOWER/CRITICAL TEMPERATURE LIMIT REGISTER (TUPPER/TLOWER/ TCRIT) → ADDRESS ‘0000 0010’b/‘0000 0011’b/‘0000 0100’b (NOTE 1) U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 — — — Sign 27°C 26°C 25°C 24°C bit 15 bit 8 R/W-0 3°C 2 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0 22°C 21°C 20°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 bit 15-13 Unimplemented: Read as ‘0’ bit 12 Sign: 0 = TA ≥ 0°C 1 = TA < 0°C bit 11-2 TUPPER/TLOWER/TCRIT: Temperature boundary trip data in two’s complement format. bit 1-0 Unimplemented: Read as ‘0’ x = Bit is unknown Note 1: This table shows two 16-bit registers for TUPPER, TLOWER and TCRIT located at ‘0000 0010b’, ‘0000 0011b’ and ‘0000 0100b’, respectively. DS22153B-page 24 © 2009 Microchip Technology Inc. MCP98243 • Writing 90°C to the TUPPER Register <0000 0101 1010 0000>b. 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 W C 1 2 3 4 5 6 7 8 0 0 0 0 0 0 1 0 SCL SDA S A K Address Byte A C K TUPPER Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 0 0 0 0 0 1 0 1 A C K 1 2 3 4 5 6 7 8 1 0 1 0 0 0 0 0 MSB Data A C K P LSB Data MCP98243 MCP98243 • Reading from the TUPPER Register. 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Note: SCL SDA S 0 0 1 1 A 2 A 1 A A 0 W C K 0 Address Byte 0 0 0 0 0 1 0 It is not necessary to select the register pointer if it was set from the previous read/write. A C K TUPPER Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 R C 1 2 3 4 5 6 7 8 0 0 0 0 0 1 0 1 1 2 3 4 5 6 7 8 1 0 1 0 0 0 0 0 SCL SDA S A K Address Byte A C K P LSB Data MSB Data MCP98243 N A K Master Master FIGURE 5-5: Timing Diagram for Writing and Reading from the TUPPER Register (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 25 MCP98243 5.1.4 AMBIENT TEMPERATURE REGISTER (TA) The MCP98243 uses a band gap temperature sensor circuit to output analog voltage proportional to absolute temperature. An internal ΔΣ 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 (TA) that contains 11-bit temperature data in two’s complement format. The TA register bits (bits 12 thru 0) are double-buffered. Therefore, the user can access the register while, in the background, the MCP98243 performs an analog-to- REGISTER 5-5: R-0 digital conversion. The temperature data from the ΔΣ ADC is loaded in parallel to the TA register at tCONV refresh rate. In addition, the TA 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 TA is greater than or equal to TCRIT, bit 14 is set to ‘1’ if TA is greater than TUPPER and bit 13 is set to ‘1’ if TA is less than TLOWER. The TA register bit assignment and boundary conditions are described in Register 5-5. AMBIENT TEMPERATURE REGISTER (TA) → ADDRESS ‘0000 0101’b (NOTE 1) R-0 R-0 TA vs. TCRIT TA vs. TUPPER TA vs. TLOWER R-0 R-0 R-0 R-0 R-0 SIGN 27 °C 26 °C 25 °C 24 °C bit 15 bit 8 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 23 °C 22 °C 21 °C 20 °C 2-1 °C 2-2 °C 2-3 °C 2-4 °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 bit 15 TA vs. TCRIT (1) Bit: 0 = TA < TCRIT 1 = TA ≥ TCRIT bit 14 TA vs. TUPPER (1) Bit: 0 = TA ≤ TUPPER 1 = TA > TUPPER bit 13 TA vs. TLOWER (1) Bit: 0 = TA ≥ TLOWER 1 = TA < TLOWER bit 12 SIGN Bit: 0 = TA ≥ 0°C 1 = TA < 0°C bit 11-0 Ambient Temperature (TA) Bits: (Note 2) 12-bit Ambient Temperature data in two’s complement format. x = Bit is unknown Note 1: Bits 15, 14 and 13 are not affected by the status of the Event output configuration (bits 5 to 0 of CONFIG) (Register 5-3). 2: Bits 2, 1, and 0 may remain clear '0' depending on the status of the resolution register (Register 5-8). The Power-up default is 0.25°C/bit, bits 1 and 0 remain clear '0'. DS22153B-page 26 © 2009 Microchip Technology Inc. MCP98243 5.1.4.1 TA bits to Temperature Conversion EQUATION 5-1: To convert the TA bits to decimal temperature, the upper three boundary bits (bits 15, 14 and 13) must be masked out. Then determine the sign bit (bit 12) to check positive or negative temperature, shift the bits accordingly and combine the upper and lower bytes of the 16-bit register. The upper byte contains data for temperatures greater than 32°C while the lower byte contains data for temperature less than 32°C, including fractional data. When combinding the upper and lower bytes, the upper byte must be Right-shifted by 4bits (or multiply by 24) and the lower byte must be Left-shifted by 4 bits (or multiply by 2-4). Adding the results of the shifted values provides the temperature data in decimal format, see Equation 5-1. BYTES TO TEMPERATURE CONVERSION Temperature ≥ 0°C 4 –4 T A = ( UpperByte × 2 + LowerByte × 2 ) Temperature < 0°C 4 –4 T A = 256 – ( UpperByte × 2 + LowerByte × 2 ) Where: TA = Ambient Temperature (°C) UpperByte = TA bit 15 to bit 8 LowerByte = TA bit 7 to bit 0 The temperature bits are in two’s compliment format, therefore, postive temperature data and negative temperature data are computed differently. Equation 5-1 shows the temperature computation. The example instruction code outlined in Figure 5-6 shows the communication flow, also see Figure 5-7 for timing diagram. This example routine assumes the variables and I2C communication subroutines are predefined: i2c_start(); // send START command i2c_write(AddressByte & 0xFE); //WRITE Command i2c_write(0x05); // Write TA Register Address //also, make sure bit 0 is cleared ‘0’ i2c_start(); //Repeat START i2c_write(AddressByte | 0x01); // READ Command //also, make sure bit 0 is Set ‘1’ UpperByte = i2c_read(ACK); // READ 8 bits //and Send ACK bit LowerByte = i2c_read(NAK); // READ 8 bits //and Send NAK bit i2c_stop(); // send STOP command //Convert the temperature data //First Check flag bits if ((UpperByte & 0x80) == 0x80){ //TA ≥ TCRIT } if ((UpperByte & 0x40) == 0x40){ //TA > TUPPER } if ((UpperByte & 0x20) == 0x20){ //TA < TLOWER } UpperByte = UpperByte & 0x1F; //Clear flag bits if ((UpperByte & 0x10) == 0x10){ //TA < 0°C UpperByte = UpperByte & 0x0F; //Clear SIGN Temperature = 256 - (UpperByte x 16 + LowerByte / 16); //TA ≥ 0°C }else Temperature = (UpperByte x 16 + LowerByte / 16); //Temperature = Ambient Temperature (°C) FIGURE 5-6: Example Instruction Code. © 2009 Microchip Technology Inc. DS22153B-page 27 MCP98243 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Note: SCL SDA S 0 0 1 A 2 1 A 1 A A 0 W C K 0 0 0 Address Byte 0 0 1 0 It is not necessary to select the register pointer if it was set from the previous read/write. A C K 1 TA Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 R C 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 1 1 2 3 4 5 6 7 8 1 0 0 1 0 1 0 0 SCL SDA S A K Address Byte A C K P LSB Data MSB Data MCP98243 N A K Master Master FIGURE 5-7: Timing Diagram for Reading +25.25°C Temperature from the TA Register (See Section 4.0 “Serial Communication”). DS22153B-page 28 © 2009 Microchip Technology Inc. MCP98243 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 MCP98243 is 0x0054 (hexadecimal). MANUFACTURER ID REGISTER (READ-ONLY) → ADDRESS ‘0000 0110’b REGISTER 5-6: 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 bit 15-0 x = Bit is unknown Device Manufacturer Identification Number . 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 W C K 1 2 3 4 5 6 7 8 0 0 0 0 0 1 1 0 Note: SCL SDA S A Address Byte It is not necessary to select the register pointer if it was set from the previous read/write. A C K Manuf. ID Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 R C 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 0 1 2 3 4 5 6 7 8 0 1 0 1 0 1 0 0 SCL SDA S A K Address Byte A C K P LSB Data MSB Data MCP98243 N A K Master Master FIGURE 5-8: Timing Diagram for Reading the Manufacturer ID Register (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 29 MCP98243 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 MCP98243 is 0x21 (hex). The revision begins with 0x01 (hex) for the first release, with the number being incremented as revised versions are released. DEVICE ID AND DEVICE REVISION (READ-ONLY) → ADDRESS ‘0000 0111’b REGISTER 5-7: R-0 R-0 R-1 R-0 R-0 R-0 R-0 R-1 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 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 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 x = Bit is unknown 8 Note: SCL SDA S 0 0 1 1 A 2 A 1 A A 0 W C K 0 Address Byte 0 0 0 0 1 1 1 It is not necessary to select the register pointer if it was set from the previous read/write. A C K Device ID Pointer MCP98243 MCP98243 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 R C 1 2 3 4 5 6 7 8 0 0 1 0 0 0 0 1 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 1 SCL SDA S A K Address Byte A C K P LSB Data MSB Data MCP98243 N A K Master Master FIGURE 5-9: Timing Diagram for Reading Device ID and Device Revision Register (See Section 4.0 “Serial Communication”). DS22153B-page 30 © 2009 Microchip Technology Inc. MCP98243 5.1.7 RESOLUTION REGISTER This register allows the user to change the sensor resolution (see Section 5.2.4 “Temperature Resolution”). The POR default resolution is 0.25°C. The selected resolution is also reflected in the Capability register (see Register 5-2). RESOLUTION → ADDRESS ‘0000 1000’b REGISTER 5-8: 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 7-3 Unimplemented: Read as ‘0’ bit 2-0 Resolution: 00 = LSB = 0.5°C (tCONV = 30 ms typical) 01 = LSB = 0.25°C (power up default, tCONV = 65 ms typical) 10 = LSB = 0.125°C (tCONV = 130 ms typical) 11 = LSB = 0.0625°C (tCONV = 260 ms typical) 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 W C 1 2 3 4 5 6 7 8 0 0 0 0 1 0 0 0 1 2 3 4 5 6 7 8 0 0 0 0 0 0 1 1 SCL SDA S Address Byte A K A C K Resolution Pointer MCP98243 A C K P Data MCP98243 MCP98243 FIGURE 5-10: Timing Diagram for Changing TA Resolution to 0.0625°C <0000 0011>b (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 31 MCP98243 5.2 5.2.1 SENSOR FEATURE DESCRIPTION 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 ISHDN. 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. 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. MCP98243 VDD Event Output RPD In Shutdown mode, all registers can be read or written. However, the serial bus activity increases the shutdown current. If the device is shutdown while the Event pin is asserted, then the Event output will be de-asserted during shutdown. It will remain de-asserted until the device is enabled for normal operation. Once the device is enabled it takes tCONV before the device re-asserts the Event output. 5.2.2 TEMPERATURE HYSTERESIS (THYST) A hysteresis of 0°C, 1.5°C, 3°C or 6°C can be selected for the TUPPER, TLOWER and TCRIT 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 hysteresis bits can not be changed if either of the lock bits, bits 6 and 7 of CONFIG, are set to ‘1’. The TUPPER, TLOWER and TCRIT 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 active-high output is selected, a pull-down resistor is requried on the Event pin. When active-low output is selected, a pull-up resistor is required on the Event pin, see Figure 5-11 and Figure 5-12 for graphical circuit description. These configurations are designed to serve processors with Low-to-High or High-to-Low edge triggered inputs. With these configurations, when the Event output De-asserts, power will not be dissipated across the pull-up or pull-down resistors. DS22153B-page 32 FIGURE 5-11: Configuration. Active-High Event Output VDD MCP98243 RPU Event Output FIGURE 5-12: Configuration. Active-Low Event Output The status of the Event output can be read using bit 4 of CONFIG (Event status). This bit can not be set to ‘1’ in shutdown mode. Bit 7 and 6 of the CONFIG register can be used to lock the TUPPER, TLOWER and TCRIT 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. © 2009 Microchip Technology Inc. MCP98243 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 5-13 shows the conditions that toggle the Event output. If the device enters Shutdown mode with asserted Event output, the output will de-assert. It will remain deasserted until the device enters Continuous Conversion mode and after the first temperature conversion is completed, tCONV. After the initial temperature conversion, TA must satisfy the TUPPER or TLOWER boundary conditions in order for Event output to be asserted. 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 TA drifts above or below TUPPER and TLOWER limits. The output is deasserted by setting bit 5 (Interrupt Clear) of CONFIG. If the device enters Shutdown mode with asserted Event output, the output will de-assert. It will remain de-asserted until the device enters Continuous Conversion mode and after the first temperature conversion is completed, tCONV. After the initial temperature conversion, TA must cross the TUPPER or TLOWER boundary conditions in order for Event output to be asserted. 5.2.4 TEMPERATURE RESOLUTION The MCP98243 is capable of providing a temperature data with 0.5°C to 0.0625°C resolution. The Resolution can selected using the Resolution register (Register 58) 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 0.25°C resolution at 125 ms (max.). The selected resolution can be read by user using bit 4 and bit 3 of the Capability register (Register 5-2). A 0.25°C resolution is set as POR default by factory. TABLE 5-2: TEMPERATURE CONVERSION TIME Resolution tCONV (ms) Samples/sec (typical) 0.5°C 30 33 0.25°C (Power-up default) 65 15 0.125°C 130 8 0.0625°C 260 4 In addition, if TA >= TCRIT the Event output is forced as Comparator mode and asserts until TA < TCRIT - THYST. While the Event output is asserted, user must send Clear Interrupt command (bit 5 of CONFIG) for Event output to de-assert, when temperature drops below the critical limit, TA < TCRIT - THYST. Otherwise, Event output remains asserted (see Figure 5-13 for graphical description). Switching from Interrupt mode to Comparator mode also de-asserts Event output. 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 MCP98243. © 2009 Microchip Technology Inc. DS22153B-page 33 MCP98243 TCRIT - THYST TCRIT TUPPER - THYST TUPPER - THYST TUPPER TA TLOWER - THYST TLOWER TLOWER -THYST (Active-Low) Event Output Comparator Interrupt S/w Int. Clear Critical Only (Active-High) Event Output Comparator Interrupt S/w Int. Clear Critical Only 2 Note: 1 1 3 4 3 5 6 7 4 2 TABLE 5-9: Event Output (Active Low/High) TA Bits Event Output Boundary Conditions Comparator Interrupt Critical 15 14 13 1 TA ≥ TLOWER Hi/Lo Lo/Hi Hi/Lo 0 0 0 2 TA < TLOWER - THYST TA > TUPPER Lo/Hi Lo/Hi Hi/Lo 0 0 1 Lo/Hi Lo/Hi Hi/Lo 0 1 0 TA ≤ TUPPER - THYST TA ≥ TCRIT Hi/Lo Lo/Hi Hi/Lo 0 0 0 Lo/Hi Lo/Hi Lo/Hi 1 1 0 Note 3 4 5 6 When TA ≥ TCRIT the Event output is forced to Comparator Mode and bits 0 of CONFIG (Event output mode) is ignored until TA < TCRIT - THYST. In the Interrupt Mode, if Interrupt is not cleared (bits 5 of CONFIG) as shown in the diagram at Note 6, then Event will remain asserted at Note 7 until Interrupt is cleared by user. 7 FIGURE 5-13: DS22153B-page 34 TA < TCRIT - THYST Lo/Hi Hi/Lo Hi/Lo 0 1 0 Event Output Condition. © 2009 Microchip Technology Inc. MCP98243 5.3 EEPROM FEATURE DESCRIPTION 5.3.1 BYTE WRITE To write a byte in the MCP98243 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 514 shows the timing diagram. 1 2 3 4 5 6 7 8 1 0 1 0 A 2 A 1 A 0 W C 1 2 3 4 5 6 7 8 X X X X X X X X 1 2 3 4 5 6 7 8 X X X X X X X X SCL SDA S A K Address Byte Word Address MCP98243 FIGURE 5-14: A C K A C K P Data MCP98243 MCP98243 Timing Diagram for Byte Write (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 35 MCP98243 5.3.2 PAGE WRITE Note: The write Address Byte, word address and the first data byte are transmitted to the MCP98243 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 MCP98243, 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 5-15). 1 2 3 4 5 6 7 8 1 0 1 0 A 2 A 1 A 0 W C 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. 1 2 3 4 5 6 7 8 X X X X X X X X SCL SDA S A K Address Byte Word Address (n) MCP98243 MCP98243 1 2 3 4 5 6 7 8 X X X X X X X X A C K 1 2 3 4 5 6 7 8 X X X X X X X X Data at (n) Note: FIGURE 5-15: DS22153B-page 36 A C K X Data at (n+1) MCP98243 A C K X X X X X A C K P Data at (n+15) MCP98243 MCP98243 n is the initial address for a page. Timing Diagram for Page Write (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. MCP98243 5.3.3 WRITE PROTECTION 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 memory 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. The MCP98243 has a Software Write-Protect (SWP) feature that allows the lower half array (addresses 00h - 7Fh) to be write-protected or permanently writeprotected (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. TABLE 5-3: WRITE PROTECT DEVICE ADDRESSING (NOTE 1) Address Pins EEPROM Operation SWP WRITE A2 A1 GND GND Address Byte A0 Address Code VHV 0110 Slave Address A2 A1 A0 0 0 1 R/W 0 READ CWP WRITE 1 GND VDD VHV 0110 0 1 1 0 READ PWP (Note) WRITE 1 X X X 0110 X X X 0 READ Note 1: 1 The Address Pins are ‘X’ or don’t cares. However, the slave address bits need to match the address pins. For VHV voltage levels, refer to Figure 2-13. TABLE 5-4: DEVICE RESPONSE WHEN WRITING DATA OR ACCESSING SWP/CWP/PWP (NOTE 1) Status Command Not Protected SWP/CWP/PWP ACK X Page/byte write ACK Address Protected with SWP Permanently Protected ACK Address ACK Data Byte ACK Write Cycle ACK X ACK Yes ACK Data ACK Yes 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 SWP/CWP/PWP NoACK X NoACK X NoACK No Page/byte write lower 128 bytes ACK Address ACK Data NoACK No Note 1: X is defined as ‘don’t care’. © 2009 Microchip Technology Inc. DS22153B-page 37 MCP98243 5.3.3.1 Software Write Protect (SWP) The Slave Address bits need to correspond to the address pin logic configuration. For SWP, a high voltage VHV needs to be applied to the A0 pin and the corresponding slave address needs to be set to ‘1’, as shown in Table 5-3. Both A2 and A1 pins are grounded and the corresponding slave address bits are set to ‘0’. The SWP feature is invoked by writing to the writeprotect register. This is done by sending an Address Byte similar to a normal Write command. Figure 5-18 shows the timing diagram. SWP can be cleared using the CWP command. See Section 5.3.3.2 “Clear Write Protect (CWP)” 1 2 3 4 5 6 7 8 0 1 1 0 0 0 1 W The device response in this mode is shown in Table 54 and Table 5-5. 1 2 3 4 5 6 7 8 X X X X X X X X 1 2 3 4 5 6 7 8 X X X X X X X X SCL SDA S A C K Address Byte Word Address A C K P Data MCP98243 MCP98243 Note: A C K MCP98243 Apply VHV at A0 pin and connect GND to A1 and A2 pins to initiate SWP cycle. FIGURE 5-16: Timing Diagram for Setting Software Write Protect (See Section 4.0 “Serial Communication”). 5.3.3.2 Clear Write Protect (CWP) The Slave Address bits need to correspond to the address pin logic configuration. For CWP, a high voltage VHV 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 VDD and the corresponding slave address bit is set to ‘1’. And A2 pins 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 Table 5-4 and Table 5-5. 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 5-18 shows the timing diagram. CWP clears SWP only. PWP can not be cleared using this command. 1 2 3 4 5 6 7 8 0 1 1 0 0 1 1 W 1 2 3 4 5 6 7 8 X X X X X X X X 1 2 3 4 5 6 7 8 X X X X X X X X SCL SDA S A C K Address Byte Word Address MCP98243 Note: A C K A C K P Data MCP98243 MCP98243 Apply VHV at A0 pin, apply VDD at A1 pin, connect A2 pin to GND to initiate CWP cycle. FIGURE 5-17: Timing Diagram for Setting Clear Write Protect (See Section 4.0 “Serial Communication”). DS22153B-page 38 © 2009 Microchip Technology Inc. MCP98243 5.3.3.3 PWP (Permanent Write Protect) Note: 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 rewritten. 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 Table 5-4 and Table 5-5). 1 2 3 4 5 6 7 8 0 1 1 0 A 2 A 1 A 0 W C Once the Permanent Write-Protect is executed, it cannot be reversed, even if the device power is cycled. See Figure 2-13 for VHV voltage levels. Unlike SWP and CWP, a VHV 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 Table 5-3. 1 2 3 4 5 6 7 8 X X X X X X X X 1 2 3 4 5 6 7 8 X X X X X X X X SCL SDA S A K Address Byte Word Address MCP98243 Note: A C K A C K P Data MCP98243 MCP98243 Unlike SWP and CWP, VHV must be within the range of GND to VDD + 1V to execute PWP. See Figure 2-13 and Section 5.3.3 “Write Protection”. FIGURE 5-18: Timing Diagram for Setting Permanent Write Protect (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 39 MCP98243 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 (NOTE) Status Command ACK Address ACK Not Protected SWP/CWP/PWP ACK X NoACK X NoACK SWP NoACK X NoACK X NoACK Protected with SWP Permanently Protected Data Byte ACK CWP ACK X NoACK X NoACK PWP ACK X NoACK X NoACK SWP/CWP/PWP NoACK X NoACK X NoACK Note: X is defined as ‘don’t care’. 5.3.4.1 Current Address Read word. The master will not acknowledge (NAK) the transfer but does generate a Stop condition and the MCP98243 discontinues transmission (Figure 5-19). The MCP98243 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 MCP98243 issues an acknowledge and transmits the 8-bit data 1 2 3 4 5 6 7 8 1 0 1 0 A 2 A 1 A 0 R C 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 0 SCL SDA S Address Byte A K FIGURE 5-19: DS22153B-page 40 P Current Word Address MCP98243 Note: N A K Master In this example, the current word address is the previously accessed address location n plus 1. Reading Current Word Address (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. MCP98243 5.3.4.2 Random Read set. The master then issues the Address Byte again, but with the R/W bit set to a ‘1’. The MCP98243 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 MCP98243 discontinues transmission (Figure 5-20). 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 MCP98243 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 1 2 3 4 5 6 7 8 1 0 1 0 A 2 A 1 A 0 W C K 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 0 SCL SDA S A Address Byte A C K Word Address (n) MCP98243 MCP98243 1 2 3 4 5 6 7 8 1 0 1 0 A 2 A 1 A 0 R C 1 2 3 4 5 6 7 8 X X X X X X X X SCL SDA S A K Address Byte P Data at (n) MCP98243 Note: N A K Master In this example, ‘n’ is the current Address Word which ‘00’h and the data is the byte at address ‘n’. FIGURE 5-20: Timing Diagram for Random Read (See Section 4.0 “Serial Communication”). © 2009 Microchip Technology Inc. DS22153B-page 41 MCP98243 5.3.4.3 Sequential Read To provide sequential reads, the MCP98243 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. Sequential reads are initiated in the same way as a random read, with the exception that after the MCP98243 transmits the first data byte, the master issues an acknowledge, as opposed to a stop condition in a random read. This directs the MCP98243 to transmit the next sequentially addressed 8-bit word (Figure 5-21). 1 2 3 4 5 6 7 8 1 0 1 0 A 2 A 1 A 0 R 1 2 3 4 5 6 7 8 X X X X X X X X SCL SDA S A C K Data (n)1 Address Byte MCP98243 MCP98243 1 2 3 4 5 6 7 8 X X X X X X X X A C K A C K 1 2 3 4 5 6 7 8 X X X X X X X X Data at (n+1) A C K X X X X X N A K P Data at (n+m)(1) Data at (n+2) MCP98243 X MCP98243 Master Note 1: ‘n’ is the initial address location and ‘m’ is the final address location (‘n+m’ < 256) FIGURE 5-21: 5.3.5 Timing Diagram for Sequential Read (See Section 4.0 “Serial Communication”). STANDBY MODE The design will incorporate a low power standby mode (ISHDN). 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. DS22153B-page 42 © 2009 Microchip Technology Inc. MCP98243 5.4 Summary of Power-on Default The MCP98243 has an internal Power-on Reset (POR) circuit. If the power supply voltage VDD glitches down to the VPOR_TS and VPOR_EE thresholds, the device resets the registers to the power-on default settings. Table 5-6 shows the power-on default summary for the temperature sensor. The EEPROM resets the address pointer to 0x00 hex. TABLE 5-6: POWER-ON RESET DEFAULTS Registers Address (Hexadecimal) Register Name Default Register Data (Hexadecimal) 0x00 Capability 0x00EF Event output de-asserts in shutdown I2C time out 25 ms to 35 ms. Accepts VHV at A0 Pin 0.25°C Measurement Resolution Measures temperature below 0°C ±1°C 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 0°C Hysteresis 0x02 TUPPER 0x0000 0°C 0x03 TLOWER 0x0000 0°C 0x04 TCRIT 0x0000 0°C 0x05 TA 0x0000 0°C 0x06 Manufacturer ID 0x0054 0x0054 (hex) 0x07 Device ID/ Device Revision 0x2101 0x2101 (hex) 0x08 Resolution 0x01 0x01 (hex) © 2009 Microchip Technology Inc. Power-up Default Register Description DS22153B-page 43 MCP98243 NOTES: DS22153B-page 44 © 2009 Microchip Technology Inc. MCP98243 6.0 APPLICATIONS INFORMATION 6.1 Layout Considerations 6.2 Thermal Considerations A potential for self-heating errors can exist if the MCP98243 SDA, SCLK and Event lines are heavily loaded with pull-ups (high current). Typically, the selfheating error is negligible because of the relatively small current consumption of the MCP98243. A temperature accuracy error of approximately 0.5°C could result from self-heating if the communication pins sink/source the maximum current specified. The MCP98243 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 µF to 1 µF be used between the VDD 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. For example, if the Event output is loaded to maximum IOL, Equation 6-1 can be used to determine the effect of self-heating. In addition, good PCB layout is key for better thermal conduction from the PCB temperature to the sensor die. For good temperature sensitivity, add a ground layer under the device pins as shown in Figure 6-1. EQUATION 6-1: EFFECT OF SELFHEATING T Δ = θ JA ( V DD • I DD + V OL_Event • I OL_Event + V OL_SDA • I OL_SDA ) Where: TΔ = TJ - TA TJ = Junction Temperature TA = Ambient Temperature θJA = Package Thermal Resistance VOL_Event, SDA = Event and SDA Output VOL (0.4 Vmax) IOL_Event, SDA = Event and SDA Output IOL (3 mAmax) At room temperature (TA = +25°C) with maximum IDD = 500 µA and VDD = 3.6V, the self-heating due to power dissipation TΔ is 0.2°C for the DFN-8 package and 0.5°C for the TSSOP-8 package. VDD A0 Event A1 EP9 FIGURE 6-1: A2 SCL GND SDA DFN Package Layout. © 2009 Microchip Technology Inc. DS22153B-page 45 MCP98243 NOTES: DS22153B-page 46 © 2009 Microchip Technology Inc. MCP98243 7.0 PACKAGING INFORMATION 7.1 Package Marking Information Example: 8-Lead 2x3x0.9 DFN XXX YWW NN ABZ 934 25 8-Lead 2x3x0.75 TDFN XXX YWW NN AAG 934 25 8-Lead 2x3x0.5 UDFN XXX YWW NN Example: AAA 934 25 Example: 8-Lead TSSOP XXXX 243B XYWW E934 NNN 256 Legend: XX...X Y YY WW NNN e3 * Note: Example: Customer-specific information Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code Pb-free JEDEC designator for Matte Tin (Sn) This package is Pb-free. The Pb-free JEDEC designator ( e3 ) can be found on the outer packaging for this package. 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. © 2009 Microchip Technology Inc. DS22153B-page 47 MCP98243 !""#$%& ' 2%& %!% *") ' % * $%%"% %% 133)))& &3 * e D b N N L K E2 E EXPOSED PAD NOTE 1 NOTE 1 2 1 1 2 D2 BOTTOM VIEW TOP VIEW A A3 A1 NOTE 2 4% & 5&% 6!&($ 55,, 6 6 67 8 9 % 7:% 9 %"$$ . 0%%* + ,2 75% /0 7;"% , ,# ""5% + < ,# "";"% , . < . ( . + 0%%5% 5 + . 0%%%,# "" = < < 0%%;"% ./0 +/0 ' !"#$%!&'(!%&! %(%")%%%" *&&# "%( %" + * ) !%" & "% ,-. /01 / & %#%! ))%!%% ,21 $& '! !)%!%%'$$&% ! .. ) 0+0 DS22153B-page 48 © 2009 Microchip Technology Inc. MCP98243 !""#$%& ' 2%& %!% *") ' % * $%%"% %% 133)))& &3 * © 2009 Microchip Technology Inc. DS22153B-page 49 MCP98243 ()""#$%*& ' 2%& %!% *") ' % * $%%"% %% 133)))& &3 * DS22153B-page 50 © 2009 Microchip Technology Inc. MCP98243 ()""#$%*& ' 2%& %!% *") ' % * $%%"% %% 133)))& &3 * © 2009 Microchip Technology Inc. DS22153B-page 51 MCP98243 + )""#$%+& ' 2%& %!% *") ' % * $%%"% %% 133)))& &3 * DS22153B-page 52 © 2009 Microchip Technology Inc. MCP98243 + )""#$%+& ' 2%& %!% *") ' % * $%%"% %% 133)))& &3 * © 2009 Microchip Technology Inc. DS22153B-page 53 MCP98243 *,-.,/-." 0 -.*1 1""#$%*..0& ' 2%& %!% *") ' % * $%%"% %% 133)))& &3 * D N E E1 NOTE 1 1 2 b e c A φ A2 A1 L L1 4% & 5&% 6!&($ 55,, 6 6 67 8 9 % 7:% < >./0 < ""** 9 . %"$$ . < . 7;"% , ""*;"% , + >/0 ""*5% + + 2%5% 5 . > . 2% % 5 . ,2 2% I ? < 9? 5"* < 5";"% ( < + ' !"#$%!&'(!%&! %(%")%%%" & ","%!"&"$ %! "$ %! %#".&& " + & "% ,-. /01 / & %#%! ))%!%% ,21 $& '! !)%!%%'$$&% ! ) 09>/ DS22153B-page 54 © 2009 Microchip Technology Inc. MCP98243 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging © 2009 Microchip Technology Inc. DS22153B-page 55 MCP98243 NOTES: DS22153B-page 56 © 2009 Microchip Technology Inc. MCP98243 APPENDIX A: REVISION HISTORY Revision B (October 2009) The following is the list of modifications: 1. Added MCP98243 vs MCP98242 comparison table. 2. Added EEPROM Write temperature Range. 3. Changed I2C time out minimum specification to 25 ms. 4. Replaced Figure 2-5. 5. Updated bits 7 and 6 of Register 5-2: Capability Register. 6. Updated Device/Revision ID register. 7. Updated Functional Block Diagram (Figure 5-1). 8. Updated Section 5.2.3.1 “Comparator Mode” and Section 5.2.3.2 “Interrupt Mode”. 9. Updated Figure 5-13. 10. Updated package marking drawings. Revision A (May 2009) • Original Release of this Document. © 2009 Microchip Technology Inc. DS22153B-page 57 MCP98243 NOTES: DS22153B-page 58 © 2009 Microchip Technology Inc. MCP98243 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. –X X /XXX Device Grade Temperature Range Package Device: MCP98243: Digital Temperature Sensor MCP98243T: Digital Temperature Sensor (Tape and Reel) Examples: a) b) MCP98243-BE/MC: Extended Temp., 8LD DFN pkg. MCP98243T-BE/MC: Tape and Reel, Extended Temp., 8LD DFN pkg. a) MCP98243-BE/ST: Extended Temp., 8LD TSSOP pkg. Grade: B B B = ±1°C (max.) from +75°C to +95°C, ±2°C (max.) from +40°C to +125°C, and ±3°C (max.) from -20°C to +125°C b) MCP98243T-BE/ST: Tape and Reel, Extended Temp., 8LD TSSOP pkg. Temperature Range: E = -40°C to +125°C a) Package: MC = Dual Flat No Lead (2x3x0.9 mm Body), 8-lead, MNY * = Dual Flat No Lead (2x3x0.75 mm Body, 8-lead (Tape and Reel) MUY * = Dual Flat No Lead (2x3x0.5 mm Body, 8-lead (Tape and Reel) ST = Plastic Thin Shrink Small Outline (4x4 mm Body), 8-lead MCP98243T-BE/MNY:Tape and Reel, Extended Temp., 8LD TDFN (nickel palladium gold) pkg. a) MCP98243T-BE/MUY:Tape and Reel. Extended Temp., 8LD UDFN (nickel palladium gold) pkg. * Y = nickel palladium gold manufacturing designator. Only available on the TDFN and UDFN packages. © 2009 Microchip Technology Inc. DS22153B-page 59 MCP98243 NOTES: DS22153B-page 60 © 2009 Microchip Technology Inc. Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained 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 in 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 products in a manner outside the operating specifications 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 semiconductor 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 committed to continuously improving 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. 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, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART, 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, Application 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, Octopus, Omniscient Code Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit, PICtail, PIC32 logo, REAL ICE, rfLAB, Select Mode, Total Endurance, TSHARC, UniWinDriver, WiperLock and ZENA are trademarks of Microchip Technology 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. © 2009, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. 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, KEELOQ® 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. © 2009 Microchip Technology Inc. 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