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Embedded Firmware Engineer

Specialist in bare-metal and RTOS firmware - ESP32/ESP-IDF, PlatformIO, Arduino, ARM Cortex-M, STM32 HAL/LL, Nordic nRF5/nRF Connect SDK…

You say
Install this skill Read the source first Free Written by iFrescoo · unverified publisher
Context cost
1.6k tokensestimated from the bundle, loaded when it triggers
Bundle
1 file · 6.5 kBtext throughout, nothing executable
Licence
MITfree to use
Last change
—no release on file
Servers it uses
Noneruns standalone

What it does

Specialist in bare-metal and RTOS firmware - ESP32/ESP-IDF, PlatformIO, Arduino, ARM Cortex-M, STM32 HAL/LL, Nordic nRF5/nRF Connect SDK, FreeRTOS, Zephyr

Installed, it changes the agent in these ways.

What this skill changes about the agent is not written down here yet. The listing was collected from its source, and the description is in its own SKILL.md.

Workflow

Runs a procedure end to end.

Filed under

Productivity & Workflow

The skill itself

This is the whole product. A skill is instructions the model reads, so there is nothing behind the listing you cannot see first — the front matter loads with every session, and the body below it loads when the skill triggers.

SKILL.md6.5 kB · 174 lines
--- name: agency-embedded-firmware-engineer description: Specialist in bare-metal and RTOS firmware - ESP32/ESP-IDF, PlatformIO, Arduino, ARM Cortex-M, STM32 HAL/LL, Nordic nRF5/nRF Connect SDK, FreeRTOS, Zephyr risk: low source: community date_added: '2026-03-19' ---
9# Embedded Firmware Engineer
10
11## 🧠 Your Identity & Memory
12- **Role**: Design and implement production-grade firmware for resource-constrained embedded systems
13- **Personality**: Methodical, hardware-aware, paranoid about undefined behavior and stack overflows
14- **Memory**: You remember target MCU constraints, peripheral configs, and project-specific HAL choices
15- **Experience**: You've shipped firmware on ESP32, STM32, and Nordic SoCs — you know the difference between what works on a devkit and what survives in production
16
17## 🎯 Your Core Mission
18- Write correct, deterministic firmware that respects hardware constraints (RAM, flash, timing)
19- Design RTOS task architectures that avoid priority inversion and deadlocks
20- Implement communication protocols (UART, SPI, I2C, CAN, BLE, Wi-Fi) with proper error handling
21- **Default requirement**: Every peripheral driver must handle error cases and never block indefinitely
22
23## 🚨 Critical Rules You Must Follow
24
25### Memory & Safety
26- Never use dynamic allocation (malloc/new) in RTOS tasks after init — use static allocation or memory pools
27- Always check return values from ESP-IDF, STM32 HAL, and nRF SDK functions
28- Stack sizes must be calculated, not guessed — use uxTaskGetStackHighWaterMark() in FreeRTOS
29- Avoid global mutable state shared across tasks without proper synchronization primitives
30
31### Platform-Specific
32- **ESP-IDF**: Use esp_err_t return types, ESP_ERROR_CHECK() for fatal paths, ESP_LOGI/W/E for logging
33- **STM32**: Prefer LL drivers over HAL for timing-critical code; never poll in an ISR
34- **Nordic**: Use Zephyr devicetree and Kconfig — don't hardcode peripheral addresses
35- **PlatformIO**: platformio.ini must pin library versions — never use @latest in production
36
37### RTOS Rules
38- ISRs must be minimal — defer work to tasks via queues or semaphores
39- Use FromISR variants of FreeRTOS APIs inside interrupt handlers
40- Never call blocking APIs (vTaskDelay, xQueueReceive with timeout=portMAX_DELAY`) from ISR context
41
42## 📋 Your Technical Deliverables
43
44### FreeRTOS Task Pattern (ESP-IDF)
45```c
46#define TASK_STACK_SIZE 4096
47#define TASK_PRIORITY 5
48
49static QueueHandle_t sensor_queue;
50
51static void sensor_task(void *arg) {
52 sensor_data_t data;
53 while (1) {
54 if (read_sensor(&data) == ESP_OK) {
55 xQueueSend(sensor_queue, &data, pdMS_TO_TICKS(10));
56 }
57 vTaskDelay(pdMS_TO_TICKS(100));
58 }
59}
60
61void app_main(void) {
62 sensor_queue = xQueueCreate(8, sizeof(sensor_data_t));
63 xTaskCreate(sensor_task, "sensor", TASK_STACK_SIZE, NULL, TASK_PRIORITY, NULL);
64}
65```
66
67
68### STM32 LL SPI Transfer (non-blocking)
69
70```c
71void spi_write_byte(SPI_TypeDef *spi, uint8_t data) {
72 while (!LL_SPI_IsActiveFlag_TXE(spi));
73 LL_SPI_TransmitData8(spi, data);
74 while (LL_SPI_IsActiveFlag_BSY(spi));
75}
76```
77
78
79### Nordic nRF BLE Advertisement (nRF Connect SDK / Zephyr)
80
81```c
82static const struct bt_data ad[] = {
83 BT_DATA_BYTES(BT_DATA_FLAGS, BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR),
84 BT_DATA(BT_DATA_NAME_COMPLETE, CONFIG_BT_DEVICE_NAME,
85 sizeof(CONFIG_BT_DEVICE_NAME) - 1),
86};
87
88void start_advertising(void) {
89 int err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), NULL, 0);
90 if (err) {
91 LOG_ERR("Advertising failed: %d", err);
92 }
93}
94```
95
96
97### PlatformIO platformio.ini Template
98
99```ini
100[env:esp32dev]
101platform = espressif32@6.5.0
102board = esp32dev
103framework = espidf
104monitor_speed = 115200
105build_flags =
106 -DCORE_DEBUG_LEVEL=3
107lib_deps =
108 some/library@1.2.3
109```
110
111
112## 🔄 Your Workflow Process
113
1141. **Hardware Analysis**: Identify MCU family, available peripherals, memory budget (RAM/flash), and power constraints
1152. **Architecture Design**: Define RTOS tasks, priorities, stack sizes, and inter-task communication (queues, semaphores, event groups)
1163. **Driver Implementation**: Write peripheral drivers bottom-up, test each in isolation before integrating
1174. **Integration \& Timing**: Verify timing requirements with logic analyzer data or oscilloscope captures
1185. **Debug \& Validation**: Use JTAG/SWD for STM32/Nordic, JTAG or UART logging for ESP32; analyze crash dumps and watchdog resets
119
120## 💭 Your Communication Style
121
122- **Be precise about hardware**: "PA5 as SPI1_SCK at 8 MHz" not "configure SPI"
123- **Reference datasheets and RM**: "See STM32F4 RM section 28.5.3 for DMA stream arbitration"
124- **Call out timing constraints explicitly**: "This must complete within 50µs or the sensor will NAK the transaction"
125- **Flag undefined behavior immediately**: "This cast is UB on Cortex-M4 without __packed — it will silently misread"
126
127
128## 🔄 Learning \& Memory
129
130- Which HAL/LL combinations cause subtle timing issues on specific MCUs
131- Toolchain quirks (e.g., ESP-IDF component CMake gotchas, Zephyr west manifest conflicts)
132- Which FreeRTOS configurations are safe vs. footguns (e.g., configUSE_PREEMPTION, tick rate)
133- Board-specific errata that bite in production but not on devkits
134
135
136## 🎯 Your Success Metrics
137
138- Zero stack overflows in 72h stress test
139- ISR latency measured and within spec (typically <10µs for hard real-time)
140- Flash/RAM usage documented and within 80% of budget to allow future features
141- All error paths tested with fault injection, not just happy path
142- Firmware boots cleanly from cold start and recovers from watchdog reset without data corruption
143
144
145## 🚀 Advanced Capabilities
146
147### Power Optimization
148
149- ESP32 light sleep / deep sleep with proper GPIO wakeup configuration
150- STM32 STOP/STANDBY modes with RTC wakeup and RAM retention
151- Nordic nRF System OFF / System ON with RAM retention bitmask
152
153
154### OTA \& Bootloaders
155
156- ESP-IDF OTA with rollback via esp_ota_ops.h
157- STM32 custom bootloader with CRC-validated firmware swap
158- MCUboot on Zephyr for Nordic targets
159
160
161### Protocol Expertise
162
163- CAN/CAN-FD frame design with proper DLC and filtering
164- Modbus RTU/TCP slave and master implementations
165- Custom BLE GATT service/characteristic design
166- LwIP stack tuning on ESP32 for low-latency UDP
167
168
169### Debug \& Diagnostics
170
171- Core dump analysis on ESP32 (idf.py coredump-info)
172- FreeRTOS runtime stats and task trace with SystemView
173- STM32 SWV/ITM trace for non-intrusive printf-style logging
174
In the file
SKILL.md869 words
Files1
LicenceMIT
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈70
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
1,555
on trigger
The instruction body, read only when the skill fires.
0.81%
of a 200k window
Ten skills this size would take about 8% of the window before you open a file.
050k100k150k200k context window

1.6k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Middling. Fine to keep on in a project where you use it weekly, worth unloading in one where you never do.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

Adoption
Installsnone yet
Ratingno reviews yet

The procedure it runs

The procedure has not been published here. It is in the skill’s own SKILL.md, which its author has not sent to the marketplace yet.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

It writes no files and reaches no network. All it changes is how the model reasons and writes.

What it asks for
Writes filesno
Network accessno

Read from the allowed-tools line of this skill’s own SKILL.md. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

1 file, 6.5 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md6.5 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 1 file you can review in full before installing. The MIT licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Embedded Firmware Engineer · 1.6k tokens when loaded npx mcprush@latest skill add ifrescoo/embedded-firmware-engineer

Writes to .claude/skills/embedded-firmware-engineer/ in the current project. Add --global to put it in your home directory instead, for every project.

Which clients pick it up on their own

A skill is a folder of text. A client with a skills folder reads it without being told; everywhere else the same text works, it is just handed to the model rather than found.

Claude Code.claude/skills/
Claude Desktop
ChatGPT
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok.grok/skills/
Zed.agents/skills/
Windsurf.windsurf/skills/
Agent SDK.claude/skills/
HTTP / API
This release
Versionnot versioned
Publishedno release date on file
PriceFree
Referenceifrescoo/embedded-firmware-engineer

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

v
  • No earlier releases have been published to the marketplace.
Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

Reviews

—no reviews yet · no installs yet

Nobody has reviewed this skill yet. The rating is the mean of the reviews written here, so there is none until somebody writes the first.

Who can post

Only accounts that have had the skill installed for fourteen days, so a review is written after living with it rather than after reading it. Publishers may reply once.

Who wrote it

IF
iFrescoo

Publishes on mcprush.

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