TC1

Pmod TC1

Contents of Readme

1. About
2. Brief information about Pmod TC1
3. Interface Description
4. Simulation
5. Tests
6. Status Information
7. Licence

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About

Simple interface for the Digilent Pmod TC1 or any other module with MAX31855.

Brief information about Pmod TC1

The Digilent Pmod TC1 is a K-Type Thermocouple Module. It contains Maxim Integrated's MAX31855 cold-junction compensated thermocouple-to-digital converter. Module communicates with the host board via SPI protocol.

Interface Description

This interface can be used to gather data from Pmod TC1 (or anything else that use MAX31855) easily.

Any of the update, update_fault and update_all can be held high for continuous reading. Output data register values are not valid when busy is set.

IOs:

Port	Type	Width	Description
clk	I	1	System Clock (Max 100 MHz)
rst	I	1	System Reset
clk_spi	I	1	SPI Clock Input (Max 5 MHz)
SCLK	O	1	SPI Clock Pin
MISO	I	1	SPI MISO Data Pin
CS	O	1	SPI Chip Select Pin
update	I	1	Update Termocoupled Temperature Register
update_fault	I	1	Update Termocoupled Temperature and Fault Register
update_all	I	1	Update All Registers
busy	O	1	Module is working and data outputs are not valid
temperature_termoc	O	14	Thermocouple Temperature Data
temperature_internal	O	12	Reference Junction Temperature Data
status	O	3	Fault flags, {Vcc,GND,Open}
fault	O	1	Indicates a fault in Termocouple

I: Input O: Output

(Synthesized) Utilization on Artix-7 XC7A35T-1CPG236C:

• Slice LUTs: 39 (as Logic)
• Slice Registers: 77 (76 as Flip Flop and 1 as Latch)

Simulation

TC1 is simulated in sim.v. Alterating MISO is generated. Pulses of update, update_fault and update_all as well as keeping update_all high simulated.

Test

The TC1 interface module tested with test module tc1_test_module.v and constrains Basys3.xdc.

tc1_test_module.v is used to control input and outputs of tc1.v. clk_spi connected to a 5 MHz clock. Same named ports of tc1_test_module.v and tc1.v connected to each other. SPI signals and busy signal are copied to upper JB header and monitored via DDiscovery. The Pmod TC1 is connected to upper JC header.

temperature_termoc is displayed on seven segment display. Left most LED is connected to fault, following 3 LEDs are connected to status and remaining LEDs are connected to temperature_internal. Buttons are used to get pulse input and switches are used to get continuous reading.

Connected Signal	Push Button	Switch
update	btnU	sw[0]
update_fault	btnR	sw[1]
update_all	btnD	sw[2]

Status Information

Last simulation: 25 April 2021, with Vivado Simulator.

Last test: 25 April 2021, on Digilent Basys 3.

License

CERN Open Hardware Licence Version 2 - Weakly Reciprocal