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1300 Henley Court Pullman, WA 99163 509.334.6306 www.digilentinc.com PmodTMP3™ Reference Manual Revised April 8, 2016 This manual applies to the PmodTMP3 rev. A Overview The Digilent PmodTMP3 is a temperature sensor built around the Microchip TCN75AVUA. Features include:         Ambient temperature sensor with up to 12bit resolution Typical accuracy of ±1 °C Programmable temperature alert pin Multiple jumpers for eight selectable addresses 30ms to 240ms typical conversion times Small PCB size for flexible designs 1.0“ × 0.8” (2.54 cm × 2.0 cm) 2×4-pin port with I2C interface Follows Digilent Pmod Interface Specification PmodTMP3 1 Functional Description The PmodTMP3 uses an 8-pin connector that allows for communication via I2C and provides pins to daisy-chain the PmodTMP3 to other I2C devices. The PmodTMP3 also provides three 3-pin headers for selecting the I2C address of the chip, and one 2-pin header for controlling external devices based upon temperature thresholds defined by the user in software. Temperature data measured by the device is formatted in two’s compliment and may be programmed for a resolution of 9-bits to 12-bits through the configuration register on the TCN75AVUA. DOC#: 502-287 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 1 of 3 PmodTMP3™ Reference Manual 2 I2C Interface The TCN75AVUA on the PmodTMP3 acts as a slave device using I2C serial communication. To communicate with the PmodTMP3, the master device must specify a slave address (0x48-0x4F) and a flag indicating whether the communication is a read (1) or a write (0). This is followed by the actual data transfer. For the TCN75AVUA, the data transfer should consist of the address of the desired device register followed by the data to be written to the specified register. To read from a register the master must write the desired register address to TCN75AVUA, then send an I2C restart condition, and send a read request to the TCN75AVUA. Pin Signal Description 1, 2 SCL I2C Clock 3, 4 SDA I2C Data 5, 6 GND Power Supply Ground 7, 8 3V3 Power Supply (3.3V) Table 1. I2C interface connector signal description. The I2C interface standard uses two signal lines. These are I2C data (SDA) and I2C clock (SCL). On the TCN75AVUA, both SDA and SCL are open-drain pins. For communication to be established, these pins must be connected to pullup resistors. The PmodTMP3 has selectable pull-up resistors on jumpers JP4 and JP5. If the master device used to communicate with the PmodTMP3 does not have pull-up resistors on the SDA and SCL signals, both JP4 and JP5 must be shorted to establish communication via I 2C. If the master device already has pull-up resistors, these jumpers may remain open. JP4 JP5 Pull-Up State Open Open Pull-ups disabled Shorted Shorted Pull-ups enabled Table 2. I2C Pull-up jumper settings. 3 I2C Address Selection The PmodTMP3 I2C bus can be set to use one of eight valid addresses. The top four bits of the address are fixed, and the three least significant bits are specified by the states of jumpers JP1, JP2 and JP3. JP1 corresponds to bit zero of the address, JP2 corresponds to bit one of the address, and JP3 corresponds to bit two of the address. The address is set by shorting the AX pin on the PmodTMP3 (where X is the bit number) with either 3V3 or GND. Shorting a jumper in the GND position corresponds to a zero while shorting a jumper in the 3V3 position corresponds to a one. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 2 of 3 PmodTMP3™ Reference Manual JP3 JP2 JP1 Address GND GND GND 0x48 (0b1001000) GND GND 3V3 0x49 (0b1001001) GND 3V3 GND 0x4A (0b1001010) GND 3V3 3V3 0x4B (0b1001011) 3V3 GND GND 0x4C (0b1001100) 3V3 GND 3V3 0x4D (0b1001101) 3V3 3V3 GND 0x4E (0b1001110) 3V3 3V3 3V3 0x4F (0b1001111) Table 3. Addresses. 4 Pinout Description Table Pin 1&5 2&6 3&7 4&8 Pin 1 2 5 Header J1 Signal Description SCL Serial Clock SDA Serial Data GND Power Supply Ground 3V3 Positive Power Supply Header J2 Signal Description AL Alert Pin GND Power Supply Ground Jumper Block JP1 JP2 JP3 JP4 JP5 JP6 Jumper Blocks State Description 3V3/GND Address bit 1 high/low 3V3/GND Address bit 2 high/low 3V3/GND Address bit 3 high/low Enabled SDA pull-up enabled Enabled SCL pull-up enabled Enabled Alert pull-up enabled Open Drain Output The PmodTMP3 provides a single open-drain header for controlling external devices based on current temperature thresholds. When the ambient temperature surpasses the value contained in the T SET register, an alert can be signaled on the AL pin of header J2. The alert may be active low or high based upon the configuration of the device and the state of JP6. Shorting JP6 pulls up the AL pin by a 2.2kOhm resistor when it is not driven by the device. The alert signal may be configured to act as a comparator output or as an interrupt. 6 Quick Start Operation When the PmodTMP3 is powered up, the onboard TCN75AVUA is in a mode that may be used as a temperature sensor without any initial configuration. The default mode of operation provides a continuous conversion, 9-bit resolution, and an active-low, comparator output alert. On power-up, the TCN75AVUA register pointer points to the Temperature register, so a two byte read without specifying a register will read the value of the temperature from the device from most significant byte (MSB) to least significant byte (LSB). For 9-bit resolution, the temperature in degrees Celsius may be calculated as a floating point value by shifting the temperature register data to the right seven bits and multiplying by 0.5. For more information on the TCN75AVUA and reading or writing to other registers on the device, please refer to the TCN75AVUA datasheet available at www.microchip.com. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 3 of 3