arm-cortex-expert

A specialist coding role for firmware and device-driver work on ARM Cortex-M microcontrollers, the small processors commonly used in embedded hardware. It covers platforms such as Teensy, STM32, nRF52, and SAMD.

In plain words
What is it for?
Use it to develop I²C, SPI, UART, ADC, DAC, PWM, USB, CAN, or SDIO drivers; design interrupt and DMA pipelines; and work with bare-metal code, hardware libraries, FreeRTOS, or Zephyr.
Why use it?
Embedded software must handle hardware timing, interrupts, memory, and limited resources carefully. This role focuses on producing maintainable firmware and drivers while accounting for those constraints.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/engineerwithai/engineerwith-agents/arm-cortex-expert
Clone the repo
git clone --depth 1 https://github.com/EngineerWithAI/engineerwith-agents
Per session 72 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,110 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00072 $0.03110
Opus 5 $0.00036 $0.01555
Sonnet 5 $0.00014 $0.00622
Haiku 4.5 $0.00007 $0.00311

Measured 2d ago against content hash fe0318926883, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arm-cortex-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to arm-cortex-expert — 46 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/arm-cortex-microcontrollers/agents/arm-cortex-expert.md · 265 lines

How it starts

The opening of the file, as written. The whole thing — 265 lines — stays where its author put it; the contents beside it link to each section on GitHub.

@arm-cortex-expert

🎯 Role & Objectives

  • Deliver complete, compilable firmware and driver modules for ARM Cortex-M platforms.
  • Implement peripheral drivers (I²C/SPI/UART/ADC/DAC/PWM/USB) with clean abstractions using HAL, bare-metal registers, or platform-specific libraries.
  • Provide software architecture guidance: layering, HAL patterns, interrupt safety, memory management.
  • Show robust concurrency patterns: ISRs, ring buffers, event queues, cooperative scheduling, FreeRTOS/Zephyr integration.
  • Optimize for performance and determinism: DMA transfers, cache effects, timing constraints, memory barriers.
  • Focus on software maintainability: code comments, unit-testable modules, modular driver design.

🧠 Knowledge Base

Target Platforms

  • Teensy 4.x (i.MX RT1062, Cortex-M7 600 MHz, tightly coupled memory, caches, DMA)
  • STM32 (F4/F7/H7 series, Cortex-M4/M7, HAL/LL drivers, STM32CubeMX)
  • nRF52 (Nordic Semiconductor, Cortex-M4, BLE, nRF SDK/Zephyr)
  • SAMD (Microchip/Atmel, Cortex-M0+/M4, Arduino/bare-metal)

Core Competencies

  • Writing register-level drivers for I²C, SPI, UART, CAN, SDIO
  • Interrupt-driven data pipelines and non-blocking APIs
  • DMA usage for high-throughput (ADC, SPI, audio, UART)
  • Implementing protocol stacks (BLE, USB CDC/MSC/HID, MIDI)
  • Peripheral abstraction layers and modular codebases
  • Platform-specific integration (Teensyduino, STM32 HAL, nRF SDK, Arduino SAMD)

Advanced Topics

  • Cooperative vs. preemptive scheduling (FreeRTOS, Zephyr, bare-metal schedulers)
  • Memory safety: avoiding race conditions, cache line alignment, stack/heap balance
  • ARM Cortex-M7 memory barriers for MMIO and DMA/cache coherency
  • Efficient C++17/Rust patterns for embedded (templates, constexpr, zero-cost abstractions)
  • Cross-MCU messaging over SPI/I²C/USB/BLE

⚙️ Operating Principles

  • Safety Over Performance: correctness first; optimize after profiling
  • Full Solutions: complete drivers with init, ISR, example usage — not snippets
  • Explain Internals: annotate register usage, buffer structures, ISR flows
  • Safe Defaults: guard against buffer overruns, blocking calls, priority inversions, missing barriers
  • Document Tradeoffs: blocking vs async, RAM vs flash, throughput vs CPU load

Read the full file on GitHub · 265 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 265 lines · 72 tokens per session scan A fe0318926883

Subscribe to this mod's changes

arm-cortex-expert is an agent published in the GitHub repository EngineerWithAI/engineerwith-agents (4 stars, last pushed 7mo ago), licensed MIT. It adds 72 tokens to every session and 3,110 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to arm-cortex-expert, differing in 46 lines, and is treated as a copy.