- About
- Brief information about Pmod TMP3
- Interface Description
- Tests
- Status Information
- Issues
- Licence
Simple interface for the Digilent Pmod TMP2 or any other module with ADT7420.
The Digilent Pmod TMP2 is a Temperature Sensor. It contains Analog Devices ADT7420 16-Bit Digital Temperature Sensor with ±0.25°C accuracy. Module communicates with the host board via I²C protocol.
This interface can be used to gather data from Pmod TMP2 (or anything else that use ADT7420) easily.
IOs:
| Port | Type | Width | Description |
|---|---|---|---|
clk |
I | 1 | System Clock |
rst |
I | 1 | System Reset |
clkI2Cx2 |
I | 1 | I²C Clock source |
SCL* |
IO | 1 | I²C Clock Pin |
SDA* |
IO | 1 | I²C Data Pin |
address_bits |
I | 2 | Address Ports of the ADT7420 |
shutdown |
I | 1 | Shutdown the module |
resolution |
I | 1 | Increase resolution, 16 bit vs 13 bit |
sps1 |
I | 1 | Enable 1 SPS mode, one measurent per second |
comparator_mode |
I | 1 | Enable comparator mode, when low interrupt mode enabled |
polarity_ct |
I | 1 | Polarity of CT Pin |
polarity_int |
I | 1 | Polarity of INT Pin |
fault_queue |
I | 2 | Fault queue configuration |
i2cBusy |
O | 1 | I²C in use by another master |
busy |
O | 1 | Module in I²C in transmisson |
sw_rst |
I | 1 | Software reset the ADT7420 |
update |
I | 1 | Get temperature reading |
one_shot |
I | 1 | Get one shot measurement, does not read the result |
write_temperature |
I | 1 | Write to temperature register |
write_temp_target |
I | 2 | Choose target temperature register |
valid_o |
O | 1 | Value in temperature_o valid |
temperature_o |
O | 16 | Temperature output |
temperature_i |
O | 16 | Temperature input |
I: Input O: Output
* contain pins _i, _o and _t
Note: rst will also software resets the ADT7420.
Note: Maximum frequency of clkI2Cx2 is 800 kHz, SCL will have half of this frequency (400 kHz). However during testing SCL frequencies above 263 kHz showed some problems during transmisson, 250 kHz worked without issues.
write_temp_target |
Register name | Width |
|---|---|---|
| 0x0 | Hysteresis | 8 bits (only lower 4 bits are used) |
| 0x1 | Critical | 16 bits |
| 0x2 | Low | 16 bits |
| 0x3 | High | 16 bits |
(Synthesized) Utilization on Artix-7 XC7A35T-1CPG236C:
- Slice LUTs: 76 (as Logic)
- Slice Registers: 54 (as Flip Flop)
The TMP2 interface module tested with test module tester_tmp2.v and constrains Basys3.xdc.
Test module handles getting data and commands from board IO and controls interface module accrodingly. A 500 kHz clock applied to clkI2Cx2. Read temperature measurements displayed on seven segment displays. I²C pins connected to upper JB header. I²C pins and alert pin are monitored via DDiscovery. Up push button used to enable/disable shutdown mode. Left push button writes the switch value in to high temperature register. Bottom push button changes configuration, taken from switches. Right push button and/or leftmost switch is used to get new reading.
Reading measurements, shutdown mode, writing to temperature registers, interrupt pin, one shot mode, changing configurations and software reset are tested.
Last test: 29 April 2021, on Digilent Basys 3.
- Some issues with
SCLfrequency. See the notes in Interface Description section.
CERN Open Hardware Licence Version 2 - Weakly Reciprocal