Adapter encoder pcb

Networked Encoder

A compact RS-485 magnetic encoder system powered by DARTT, designed for daisy-chaining multiple encoder nodes on a shared bus. The system consists of STM32-based firmware, a host-side C++ API, and a CLI tool for calibration, address assignment, and firmware flashing.

What it does

Each encoder node sits on an RS-485 bus and responds to two address classes:

• Motor address — a minimal framing mode optimized for high-rate angle polling, intended for real-time motion control.
• Misc address — full DARTT register access for calibration (sin/cos bounds, angular offset, orthogonality error), device control (save to flash, restart, enter bootloader), and diagnostics.

Addresses are assigned per-device and persisted to flash. The bootloader (also DARTT-based) supports firmware updates over the same RS-485 bus with no additional hardware interface.

Repository Structure

Dependencies

The API and CLI pull in three submodules under api/external/:

Initialize all submodules after cloning with git submodule update --init --recursive.

Building

Requires CMake 3.22+ and a C++20-capable compiler. The primary build target is encoder-cli. VSCode launch and build tasks are provided in .vscode/.

CLI

The CLI (encoder-cli) takes a DARTT device address as its first argument followed by a port and baud rate. It supports streaming angle data, reading raw ADC values, running an interactive calibration session, reassigning device addresses, and flashing firmware over RS-485 via the bootloader. Run encoder-cli --help for the full command reference.

First-time Device Setup

Use scripts/init_flash.sh to set up a brand-new device. The bootloader ships at address 255 and the encoder application defaults to address 0. The script flashes firmware, starts the application, then assigns a permanent address. For subsequent updates on an already-configured device, use scripts/update_firmware.sh.

Using the API

api/ is designed to be consumed as a CMake add_subdirectory dependency. Link against encoder_controller and construct an Encoder object with the device address and a pointer to an already-connected Serial object. The caller owns the Serial lifetime.