RTTShell – CLI workbench for embedded firmware debugging

Turn J-Link RTT into a scriptable, CI-ready command-line debug and verification tool

Problem

Firmware developers burn, open a UART terminal, type commands, and eyeball output for every change. Each cycle takes a minute or two and regression testing relies on memory, so things get missed. UART is often occupied by app logs or not broken out, serial ports are hard to enumerate in CI, multi-board parallel runs are painful, and flashing lives in a separate tool from verification.

Solution

A CLI that opens an interactive RTT terminal over J-Link and also supports a "send one line, wait for a reply" script mode. It runs batches of verification cases, exports data, and can run headless inside CI. Flashing steps are wrapped into the same flow so programming and validation share one pipeline.

Users

Embedded firmware engineers, hardware startup teams, developers who want board-level verification inside CI

MVP

Windows/macOS CLI depending on the J-Link DLL; interactive RTT terminal; command-reply scripting mode; JSON/CSV data export; non-interactive CI entry point

Revenue

Open-source core plus a one-time commercial license (e.g. $49/seat) or team license; annual subscription for enterprise CI support.

Why now

The J-Link user base is large but SEGGER's RTT-Viewer is clunky and lacks a good CLI wrapper. LLM-assisted coding makes a cross-platform .NET CLI cheap for one person to build, and embedded communities spread good tools fast by word of mouth.