PmodTMP2 Reference Manual

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I

The PmodTMP2 I

of four valid addresses. The top five bits of the

address are fixed, and the two least significant

bits are taken from the jumper states of JP2

and JP1. JP2 corresponds to bit one of the

address while JP1 corresponds to bit zero. An

open jumper corresponds to a one in the

address while a shorted jumper corresponds to

a zero. For example, when JP2 and JP1 are

open the device uses the address 0x4B

(0b1001011).

Open Drain Outputs

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

(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

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.

Quickstart Operation

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.

Addresses

JP2

JP1

Address

Open

Open

0x4B (0b1001011)

Open

Shorted

0x4A (0b1001010)

Shorted

Open

0x49 (0b1001001)

Shorted

Shorted

0x48 (0b1001000)