esp32-wroom-38pin

esp32-wroom-38pin is a skill for Claude Code, Codex from alexex1993/mcu-skills. It costs 0 tokens per session (4,515 once invoked), scanned A, original, MIT.

A firmware development guide for 38-pin ESP32-WROOM-32 development boards, including common DevKitC, NodeMCU, and DOIT versions. It explains the exposed pins, USB bridge, boot controls, flash connections, and power setup.

In plain words
What is it for?
Use it to choose safe pins, configure the development tools, set flash partitions, write peripheral code, and recover or flash the board.
Why use it?
This board exposes pins used by the built-in flash memory and boot process, so choosing the wrong pin can stop the chip from starting or damage normal operation.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: reads .claude/ paths.

Good fit Use it to choose safe pins, configure the development tools, set flash partitions, write peripheral code, and recover or flash the board.

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Install with agentmods
npx agentmods add skills/alexex1993/mcu-skills/esp32-wroom-38pin
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.

Any agent
npx skills add alexex1993/mcu-skills --skill esp32-wroom-38pin
Clone the repo
git clone --depth 1 https://github.com/alexex1993/mcu-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for esp32-wroom-38pin

README.md
[![agentmods](https://agentmods.dev/badge/skills/alexex1993/mcu-skills/esp32-wroom-38pin/github.svg)](https://agentmods.dev/skills/alexex1993/mcu-skills/esp32-wroom-38pin)
Your own site
<a href="https://agentmods.dev/skills/alexex1993/mcu-skills/esp32-wroom-38pin"><img src="https://agentmods.dev/badge/skills/alexex1993/mcu-skills/esp32-wroom-38pin/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for esp32-wroom-38pin

Your own site · 80×15
<a href="https://agentmods.dev/skills/alexex1993/mcu-skills/esp32-wroom-38pin"><img src="https://agentmods.dev/badge/skills/alexex1993/mcu-skills/esp32-wroom-38pin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,515 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium analysis-evasion · line 1
    Suspicious Unicode normalization or mixed-script content
    Fix: Review the flagged content for security risks. Ensure no credentials, secrets, or sensitive data are exposed.
How audits are shown
Origin original No closer match found 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 5.1 $0.00000 $0.04515
Opus 5 $0.00000 $0.02257
Sonnet 5 $0.00000 $0.00903
Haiku 4.5 $0.00000 $0.00451

Measured 8d ago against content hash 8b8d6d146f01, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

esp32-wroom-38pin 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 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (template/variants/new-project.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/esp32/esp32-wroom-38pin/SKILL.md · 251 lines

How it starts

The opening of the file, as written. The whole thing — 251 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ESP32-WROOM-32 devkit — 38-pin

The reference form factor: Espressif's ESP32-DevKitC V4 and the clones that copy its J2/J3 header pin for pin. Nineteen pins a side, and every pad of the module is broken out — including six that will hang the chip and one that will stop it booting.

That completeness is the whole story of this board. The 30-pin version protects you by omission; this one hands you the flash bus and GPIO0 and expects you to know better. Read reference/board-hardware.md before choosing pins.

  • reference/board-hardware.md — the board: the Espressif J2/J3 header table with every pin's alternate functions, the six flash pins, the IO0 hazard, the D2-means-GPIO9 silkscreen trap, the WROVER GPIO16/17 difference, the USB bridge and auto-reset circuit, power tree, flash partitions — plus a development guide (§10 toolchain, §11 sdkconfig, §12 flashing and recovery, §13 peripheral cookbook, §14 symptom → cause → fix table).
  • reference/esp32-soc.md — the silicon: pins that do not exist, strapping semantics and the GPIO_STRAP_REG bit order, ADC/DAC/touch maps and accuracy, IO_MUX vs GPIO Matrix and the SPI speed rule, power modes, memory map, deep-sleep wake pins.
  • reference/esp32-family.md — the rest of the family, for "should this be a different ESP32?" questions: what does and does not port between chips, radio and USB capability per chip, the RMT generation table (WS2812 under Wi-Fi load), deep-sleep memory and ULP/LP-core availability, and a chip-selection table.
  • reference/recipes.md — code that compiles: platformio.ini, sdkconfig.defaults, ADC1 with calibration, LEDC LED and servo, debounced input, the new I2C master driver, 80 MHz SPI, UART2, Wi-Fi scan and station connect, NVS, deep sleep, RMT WS2812.
  • template/ — a project that builds clean, in two variants, plus a scaffold script. See template/README.md.

Orientation

Module ESP32-WROOM-32/-32D/-32E/-32U, ESP-WROOM-32S, or ESP32-WROVER — check the can. ESP32-D0WDQ6 or D0WD-V3, Xtensa LX6 dual-core @ 240 MHz
Memory 4 MB in-package flash, 520 KB SRAM (~320 KB linkable), 8 KB RTC FAST + 8 KB RTC SLOW. PSRAM only on a WROVER
Header 38 pins, 19 per side (Espressif J2 / J3). 32 GPIOs — all module pads, EN, 3V3, 5V, 3× GND
USB No USB peripheral in the chip. A CP2102N (DevKitC) or CH340G (clones) bridge on UART0 (GPIO1/GPIO3), with DTR/RTS auto-reset
Console UART0 @ 115200 only. There is no USB-Serial-JTAG and no debug header
LED none on the Espressif DevKitC V4. GPIO2, active high, on NodeMCU-32S and clones
Buttons BOOT = GPIO0, pressed low, and GPIO0 is also a header pin · EN/RST acts on CHIP_PU, not readable
Free pins 4, 13, 14, 16, 17, 18, 19, 21, 22, 23, 25, 26, 27, 32, 33
Input-only 34, 35, 36 (VP), 39 (VN) — no output driver, no internal pulls
Strapping 0, 2, 5, 12 (MTDI), 15 (MTDO)
Never use 6, 7, 8, 9, 10, 11 — the in-package flash bus, six pins by the USB connector
Analog ADC1 on 32–36, 39 · ADC2 on 0, 2, 4, 12–15, 25–27 · DAC on 25 and 26
Radio Wi-Fi b/g/n + Bluetooth 4.2 BR/EDR + BLE, PCB antenna (or u.FL on -U/-IE modules)
Power 3V3 out (~600 mA budget) · 5V in/out. Three mutually exclusive supply routes
Toolchain PlatformIO 6.1.19 + platform-espressif32 7.0.1 + ESP-IDF 6.0.1, board = esp32dev

Read the full file on GitHub · 251 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. 8d ago Changed · +4 lines 8b8d6d146f01
  2. 12d ago First seen · 247 lines · 0 tokens per session scan A da2b1bd64911

Subscribe to this mod's changes

esp32-wroom-38pin is a skill published in the GitHub repository alexex1993/mcu-skills (17 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 4,515 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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