IO Modules (modbus, stm32)

This repository is the result of work on the I/O module (especially parameterized EOL inputs) for Raspberry Pi / Orange Pi boards. The project has quite a long history, described in more detail in http://blog.opcode.eu.org/2021/12/27/mikrokontroler_w_sterowaniu.html (in polish).

project status

This is currently not a production solution. Rather, it is set of ideas, concepts, example circuits, etc, published for educational purposes. It can be useful in creating these types of projects and solutions, but for real use it requires more tests.

used eda & pcb software

All schematics are made using lepton-eda / gEDA with my symbols library. All PCBs are made using pcb-rnd.

project components

• I/O circuits schematics and „submodules” PCB
  • different I/O types:
    • bus:
      • CAN
      • RS485
      • RS232
    • input:
      • optoisolated (digital or 3EOL)
      • analog with opamp
    • output:
      • half H bridge
      • open drain / open collector
      • AC (triac)
      • current/voltage analog with opamp
  • uC minimodules connector subcircuits with eeprom and 1wire interface (for use in mainboards)
  • PCB files can be included in bigger PCB projects (see docs/how_to_use_submodules.txt)
  • see submodules directory (and docs/analog_INPUT_and_3EOL.sch for general input concepts)
• uC minimodules with RS485 interface and LDO
  • 3 variants with STM32G030KxT (or similar uC) and different RS485 transmiter control
  • see main_boards directory
  • for development purpose is possible use STM32F103xC too – see docs/STM32F103xC.png
• master board schematics
  • concept circuits for use *Pi board as master with bus control
  • concept circuits for system powering
    • DC/DC converter for 5V power (for *Pi board and bus power for I/O modules)
    • 5V → 3.3V LDO on uC minimodules for power I/O modules
  • see master_board directory
• mainbord with included I/O „submodules” and uC connector
  • currently 4 variants with different number/types of I/O
  • see main_boards directory
• software for uC
  • modbus RTU (over RS485) for bus-communication (see stm32-modbusrtu project)
  • software jump to bootloader for remote reprogramming I/O modules from master – see docs/UART_Communication_and_Programming.md
  • read inputs concept – see docs/read_inputs.md
  • implementation does not exist yet