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Adding a System-on-a-Chip or Microcontroller

DeviceScript currently supports the following:

  • ESP32, including the "classic", S2, S3, and C3 variants
  • RP2040, including Raspberry Pi Pico and Pico W
  • WASM and POSIX for simulation

Following are work-in-progress:

  • STM32, specifically STM32L475VG

If you're working on a port, let us know (via GitHub issue or discussion) so we can list is here.

Generally, DeviceScript has a concept of an "architecture" which corresponds 1:1 to an executable binary, which is a specific SoC/MCU or a family thereof (we use SoC (System-on-a-Chip) and MCU (Microcontroller Unit) interchangably in this document).

For example, for ESP32 there are esp32, esp32c3, esp32s2, and esp32s3 architectures. For RP2040, we have two architectures: rp2040 (generic) and rp2040w (with support for WiFi chip from Pico W). For STM32, it may be possible in future to have say a single stm32l4 architecture that then dynamically adds enables support for peripherals that are present and auto-detects the size of RAM and FLASH, but right now we just have a specific stm32l475vg.

DeviceScript further defines "boards" which take a binary architecture image and binary-edit it to include configuration data about pin names and on-board peripherals.

Note, that there isn't any shared code for say "ARM" or "RISC-V" architecture, as all the VM code is platform-agnostic C anyways, which sits in the main DeviceScript repo.

Creating new SoC​

It's best to start by forking an existing port, we suggest the rp2040 one, and implement functions one by one. Start by looking at jd_user_config.h file and disable things.

Note that the STM32 port borrows heavily from Jacdac firmware for STM32G0-based modules, so parts of the source are not necessary for DeviceScript. If you want to use STM32 as a base, it's likely better to use rp2040 or esp32 as the skeleton, and copy code from the STM32 as needed.

As for SoC requirements:

  • make sure your SoC has enough memory
  • it's highly recommended to use SoCs with built-in USB peripheral; we do have some support for using external USB-UART chips (as in ESP32 classic port) but it's rather buggy