Interface module

mints-scada-hardware

Minimal Test Stand Supervisory Control and Data Acquisition system hardware and firmware. See mints-scada-software for the computer software to control the whole system.

Assembly

stm32devboards

• Populate all SMD components on the board
  • Only populate the 60.4 ohm CAN termination resistors on the nodes on the ends of the chain.
  • Populate the USB port and solder its mounting lugs
  • Do not populate the headers on the sides as they will make it more difficult to work on the boards if problems are discovered
• Complete the board testing
• Populate THT components

interface-module

• Select the desired configuration of the board. This can be one of
  • 8x Push and/or Pull outputs
  • 4x I2C
  • 4x ADC
  • See notes in KiCad for configuration information
• Assemble only the required components for that version of the board. Leave the rest unpopulated

Firmware flashing

Firmware files are located in the firmware/bin directory.

Command line (recommended)

Command line firmware flashing instructions are provided for Ubuntu 24.04. Other debian-based Linux distros should follow a similar procedure. Flashing from Mac or Windows should be possible, but is not covered here.

Setup

1. Install dfu-util with sudo apt install dfu-util
2. Set up udev rules
   1. Put the following into /etc/udev/rules.d/60-stm32

   # STM32
   ACTION=="add", SUBSYSTEM=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="df11", TAG+="uaccess"

   2. Either reboot or run sudo udevadm control --reload-rules && sudo udevadm trigger to reload the udev rules

Flashing:

1. Remove the devboard from the module if it was installed.
2. Put the device in bootloader mode
   • If the device is unplugged, hold the BOOT button while plugging it in
   • If the device is already plugged in, press RESET and BOOT, then release RESET then BOOT
3. Run dfu-util --list and confirm that there are two devices with the vendor:product ID 0483:df11, one with the name @Option Bytes and one with the name @Internal Flash. If any other devices with that ID are present, remove them before continuing.
4. Flash the device with dfu-util --device 0483:df11 --alt 0 --dfuse-address 0x08000000:leave --download [path/to/file/]<filename>.bin. It should erase the flash, then download the new file and show File downloaded successfully when it is done.

Visual

STM32CubeProgrammer can be used to flash device firmware. Setup will be platform-dependent, and thusly not covered here.

To build and upload:

1. Open the PlatformIO tab in the left toolbar
2. Under PROJECT TASKS > Build > General execute the Build procedure by clicking on it
3. Execute Upload to upload to the microcontroller. Ensure that only a single board is plugged in to ensure you are writing to the correct device.

Building Firmware

Building firmware from source shouldn't be needed unless you are making changes to it. Firmware build instructions are provided for Ubuntu 24.04. Other debian-based Linux distros should follow a similar procedure. Flashing from Mac or Windows should be possible, but is not covered here.

You will need:

• GCC for arm sudo apt install gcc-arm-none-eabi
• make sudo apt install make
• Everything as described in the command line flashing setup section above.

To build the code, simply run make in the firmware folder. This will build the firmware and copy the .bin into the firmware folder. Running make flash will build the firmware then upload it to a connected DFU mode microcontroller.

Initialization code was generated using [https://www.st.com/en/development-tools/stm32cubemx.html](STM32Cube initialization code generator). You should not need to mofidy this, but if you do, the module_io.ioc is included. If you regenerate the code, you may have to add

#######################################
# Flash
#######################################
flash: all
	dfu-util --device 0483:df11 --alt 0 --dfuse-address 0x08000000:leave --download $(BUILD_DIR)/$(TARGET).bin

to the end of Makefile. Optionally, add cp $(BUILD_DIR)/$(TARGET).bin $(TARGET).bin to target all in the makefile (add line 171) to copy the bin out of the build direcotry. Generally, CubeMX does not seem to update the Makefile if it exists.

Testing

stm32devboards

1. Populate all SMD components as described in the assembly sections. Do not populate THT components yet
2. Visually inspect the board. Fix any issues and inspect again until no issues remain
   • Verify that no pins are shorted
   • Verify the correct orientation and alignment of all components. Pay special attention to the STM32 since its square shape makes it more difficult to notice errors
   • Bridges can hide under the USB port where you can't see them unless you tilt the board to look deep under the port. They can often be fixed by applying flux then heating the two bridged pins.
   • Fixing any of these issues is easier before soldering THT parts since everything here is reflow safe, so it is less likely to be damaged during repairs.
3. Use a DMM to test between GND 3v3, and GND and either pad of the polyfuse (the component in the corner of the board by the USB port). Verify there are no shorts.
4. On your computer run sudo dmesg -Hw to monitor system messages in real time (-m) with human-readable timestamps (-h). Keep this window open and visible for the next step
5. Plug the board in via USB. Watch dmesg. The following should appear. If it does not, then there is a problem with your board.

[<starttime>] usb 3-2: new full-speed USB device number <id> using xhci_hcd
[  +0.148877] usb 3-2: New USB device found, idVendor=0483, idProduct=df11, bcdDevice=22.00
[  +0.000014] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  +0.000006] usb 3-2: Product: STM32  BOOTLOADER
[  +0.000006] usb 3-2: Manufacturer: STMicroelectronics
[  +0.000005] usb 3-2: SerialNumber: FFFFFFFEFFFF

6. Use the above procedure to flash the blink-fast.bin firmware. Confirm that the LED blinks at about 10Hz.
7. Use the above procedure to flash the blink-slow.bin firmware. Confirm that the LED blinks at about 1Hz. This confirms that you are able to flash new firmware to the device.
8. Install the THT components as described in the assembly section.

blink-fast.bin and blink-slow.bin should already be built in the firmware/bin directory. If they are not, they can be rebuilt with the blink project. To rebuild them, run the following in firmware/blink

make clean && make DELAY=500 && cp blink.bin ../bin/blink-slow.bin
make clean && make DELAY=50 && cp blink.bin ../bin/blink-fast.bin