This repository contains the firmware for the Keithley SCAN2000 SSR replacement pcb found here and here.
It supports 20 channel and 10 channel operation, as well as 4W. It is based on the version from Patrick Baus, that I unfortunately found to be not functioning, as several bugs were available. So I debugged it and added some more debugging functionality to it.
A compiled version can be found in the /build folder.
The source code is based on the project by George Christidis. It uses CubeMX instead and it makes use of the STM32 HAL labraries instead of the low-level libraries. It can be built using a Makefile.
To flash the SMT32G0, I use an ST-Link programmer along with STM32CubeProgrammer.
To flash the firmware to the microcontroller do the following:
- Compile the code using the Makefile. In Linux type make. Alternatively use the compiled firware in the /build folder.
- Power the MCU via the 5V pin. It should draw about 40 mA @ 5V and the Power led should be lit.
- Connect the ST-link programmer via the header and the adapter board.
- Open STM32CubeProgrammer and press connect
- Now open load the .hex file and press download. STM32CubeProgrammer should report success and the board current should now drop to < 10 mA.
- In the STM32CubeProgrammer window press disconnect. The board power typically increases by 1 mA.
- Disconnect the ST-Link
- Reset the MCU. The Activity led should flash twice to signal a successful boot. The board should now draw about 15 mA during idle and both LEDs should be lit.
If you want the read back what the MCU is doing, hook up a TTL to USB converter to the TX and GND pins. I use a Waveshare Industrial USB TO TTL Converter, but any of the cheap Ebay FT232 modules works. The parameters are 115200 baud, 8 bits, no parity, 1 stop bit.
To configure a Linux tty, type the following commands. Do make sure to change the tty to your tty. This example uses /dev/ttyUSB5.
stty -F /dev/ttyUSB5 115200 cs8 -cstopb -parenb echo -echoe -echok -echoctl -igncr -icanonThe firmware logs every message in a rather verbose manner (outside of the interrupt handler), with timestamps.
When you enable #define LOG_DEBUG_MESSAGES in main.c, the activity led is lit only during interrupt handler activity. This will allow you to see if the interrupt handler is fast enough or if it hangs.
- This code has not been tested yet under a SCAN2000 (10 channel) emulation. Looking at the code, it should work, but I have not tested it.
See the following repositories for more information
Keithley SCAN2000 Hardware: https://github.com/hb020/SCAN2000. That is a forked and slightly improved version of https://github.com/PatrickBaus/SCAN2000
This project is licensed under the GPL v3 license - see the LICENSE file for details