It is necessary to design a board that will have an STM32, connected to a MAX485, a CAN bus transceiver, an HX711 microchip, and three MOSFET transistors that act as an LED driver.
I previously used a ready-made STM32 blue pill module. Instead, it will be necessary to lay out the circuit on this board. I will only use an 8MHz crystal. LPOSC is not needed. The status LED and the RESET button will also be kept. The board will be manufactured in large quantities, so everything needs to be done on one side to avoid high assembly costs.
Please also pay attention to geometrically separating the transistors from the rest so that noise from the MOSFETs does not interfere with the operation of the ADC and other microchips.
Elements marked in blue and mounting holes (diameter 4.1 mm - center of the hole 10mm from the edge) must remain in their existing places. The connector at the bottom marked in blue and green should have 3 contacts: 5V, 12V, and GND. It will also be necessary to add connectors for the CAN bus. They are marked in gray; please note that they are not in the center but offset to the side. The connectors should be placed at the edge of the board. I also need to add a silk-screening area to label the board.
I am also attaching a project with a schematic diagram (NewRowController_schemOnly.eprj), which is not fully completed. It is necessary to select transistors that can be controlled by the STM32, meaning that the transistor should fully turn on at 3.3V.
It is also necessary to connect the bases of the transistors and the HX711 to the STM32 microcontroller. They can be connected to any free pins of the microcontroller.
StepX_slave_board.eprj - there is the board from the screenshot.
It is necessary to check the existing schematic diagram. If needed, replace components as I mentioned about the transistors, or it may also be possible to replace the MAX485 with some 3.3V compatible analog.
Properly design the analog and power sections of the board.
I expect the project files, BOM, and Gerber.
The BOM is best from JLCPCB Stock so that it can be ordered from them immediately.
