PmodTMP2™ Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
2.1 OpenDrainOutputs
The PmodTMP2 provides two open drain output headers for controlling external devices based upon current
temperature thresholds. If the temperature leaves a range defined by registers TLOW (0x06:0x07) and THIGH
(0x04:0x05) then the INT pin on J3 can be driven low or high based upon the configuration of the device. Similarly,
the CT pin on J2 can be driven low or high if the temperature exceeds a critical threshold defined in TCRIT
(0x08:0x09). Both of these pins are pulled up by 10KOhm resistors when they are not driven by the device. For
details on their electrical specifications and configuration of the INT and CT pins please refer to the ADT7420
datasheet.
2.2 QuickStartOperation
When the PmodTMP2 is powered up, the onboard ADT7420 is in a mode that can be used as a simple temperature
sensor without any initial configuration. By default, the device address register points to the temperature MSB
register, so a two byte read without specifying a register will read the value of the temperature register from the
device. The first byte read back will be the most significant byte (MSB) of the temperature data, and the second
will be the least significant byte (LSB) of the data. These two bytes form a two’s complement 16-bit integer, if the
result is shifted to the right three bits and multiplied by 0.0625 the resulting signed floating point value will be a
temperature reading in degrees Celsius.
For information on reading and writing to the other registers of the device, as well as notes on the accuracy of the
temperature measurements please refer to the ADT7420 datasheet.
