STM32 Development

Hardware
,
242

For those interested here is a rough outline of my STM32 development plan

STM32

Goals of the project:

  • Higher resolution 12 bit ADCs
  • Higher sampling rate
  • Continuous sampling on all Voltage and Current channels
  • Shield/extension design
  • RaspberryPi core, local datastorage, visualisation
  • Learning resources on the STM32 platform to enable modification & customisation.

Steps:

  1. Work through STM32 power supply, clock, programming sub circuits, check understanding, component sourcing. Put together base board design (equivalent of a STM blue pill, or Ken’s ARMIGO) potentially with a couple of CT and ACAC sensor inputs for initial testing.

  2. Filter design for CT and ACAC voltage input circuits.

  3. Construct 3D model of enclosure options, visualise different stacking design options, connectors, raspberrypi location. Ease of manufacture & assembly.

  4. Verify MBUS reader running on STM32 alongside energy monitoring code.

  5. Understand @dBC one wire code and timing implications.

  6. Review base-board feature requirements:

    • STM32 core and pin count
    • Number of CT sensor inputs
    • CT sensor mapping to ADC channels
      sequential vs parallel sampling capabilities.
    • Number of ACAC Voltage inputs
    • DS18B20, pulse counting connector types and numbers.
    • MBUS
    • RaspberryPi connector and mounting
    • ESP8266 on board
    • RFM69 support
    • RTC
    • Display & push button

Evaluate cost implications of including on board vs requiring shield additions for items such as MBUS, RFM69 & ESP8266.

  1. Create PCB layout for first hardware design. Get prototypes, testing, fix issues, EMC prelim, design iteration and revaluation of next steps from this point.

I will keep updating as this progresses. This is work I’m doing alongside emoncms and emoncms.org development and so development will be a little discontinuous at times.