- About
- Brief information about Pmod TMP3
- Interface Description
- Tests
- Status Information
- Issues
- Licence
Simple interface for the Digilent Pmod TMP3 or any other module with TCN75A.
The Digilent Pmod TMP3 is a Temperature Sensor. It contains Microchip's TCN75A 2-Wire Serial Temperature Sensor. TCN75A digital temperature sensor converts temperatures between -40°C and +125°C to a digital word, with ±1°C (typical) accuracy. Module communicates with the host board via I²C protocol.
his interface can be used to gather data from Pmod TMP3 (or anything else that use TCN75A) 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 |
3 | 1 | Address pins of TCN75A |
shutdown |
I | 1 | Shutdown module |
resolution |
I | 2 | Measurement resolution |
alert_polarity |
I | 1 | Alert polarity |
fault_queue |
I | 2 | Fault queue configuration |
interrupt_mode |
I | 1 | Enable alert interrupt mode |
i2cBusy |
O | 1 | I²C in use by another master |
busy |
O | 1 | Module in I²C in transmission |
update |
I | 1 | Get temperature reading |
write_temperature |
I | 1 | Write to temperature register |
write_hyst_nLim |
I | 1 | Choose temperature register; 1: Hyst, 0: Limit |
valid_o |
O | 1 | Value in temperature_o valid |
temperature_o |
O | 12 | Temperature output |
temperature_i |
O | 9 | Temperature input |
I: Input O: Output
* contain pins _i, _o and _t
Note: Maximum frequency of clkI2Cx2 is 800 kHz, SCL will have half of this frequency.
(Synthesized) Utilization on Artix-7 XC7A35T-1CPG236C:
- Slice LUTs: 61 (as Logic)
- Slice Registers: 52 (as Flip Flop)
The TMP3 interface module tested with test module tester_tmp3.v and constrains Basys3.xdc.
Test module handles getting data and commands from board IO and controls interface module accordingly. A 800 kHz clock applied to clkI2Cx2. Leftmost switch is connected to shutdown, following switch to write_hyst_nLim. Next switch used to read temperature continuously. Remaining switches used to gather data. Upper button used to write to temperature registers, bottom button to update configurations and right to get a new reading. Read temperature measurements displayed on seven segment displays. I²C pins connected to upper JB header. I²C pins and alert pin are monitored via DDiscovery.
Reading measurements, shutdown mode, writing to temperature registers and all alert options are tested.
Last test: 27 April 2021, on Digilent Basys 3.
- Some glitches in
SDA, only whenSCLis low. - Some issues with on board pull-up resistors.
- Continuous read from temperature register causes NACK after a few reads (~13). This doesn't brake the system.
CERN Open Hardware Licence Version 2 - Weakly Reciprocal