# Gpio Baremetal

> Bare-metal GPIO skill for pin configuration and interrupts. Use when configuring GPIO modes, alternate functions, pull resistors, or EXTI interrupts on STM32/nRF/ESP32-class MCUs. Activates on queries about GPIO MODER, alternate function, pin interrupt, or LED/button bare-metal setup.

- **Type:** Skill
- **Install:** `agentstack add skill-mohitmishra786-low-level-dev-skills-gpio-baremetal`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [mohitmishra786](https://agentstack.voostack.com/s/mohitmishra786)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [mohitmishra786](https://github.com/mohitmishra786)
- **Source:** https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/baremetal/gpio-baremetal
- **Website:** https://www.lowleveldevskills.com

## Install

```sh
agentstack add skill-mohitmishra786-low-level-dev-skills-gpio-baremetal
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# GPIO (Bare-Metal)

## Purpose

Configure and use GPIO without HAL: input/output modes, alternate function mapping, pull-up/down, speed/slew, and pin-change interrupts for LEDs, buttons, and peripheral pin mux.

## When to Use

- Blink LED or read button before bringing up UART/SPI
- Mux pins to USART/SPI alternate functions
- EXTI line interrupts on pin edges
- Porting GPIO code between vendors

## Workflow

### 1. STM32 GPIO pattern

```c
/* Enable GPIOA clock */
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;

/* PA5 output — MODER[11:10] = 01 */
GPIOA->MODER &= ~(3U MODER |=  (1U BSRR = (1U BSRR = (1U MODER &= ~(3U MODER |=  (2U AFR[0] &= ~(0xFU AFR[0] |=  (7U MODER &= ~(3U PUPDR &= ~(3U PUPDR |=  (1U IDR & (1U EXTICR[3] = (SYSCFG->EXTICR[3] & ~0xFU) | 0x2;  /* port C */
EXTI->IMR  |= (1U FTSR |= (1U PR`, clear with write-1.

### 4. nRF52 / ESP32 notes

| Platform | Pattern |
|----------|---------|
| nRF52 | `NRF_P0->PIN_CNF[n]` — direction, pull, drive |
| ESP32 | `GPIO.out_w1ts`, `GPIO.enable`; IO_MUX for function |

Always enable peripheral clock / power domain before pin config.

### 5. Agent usage

```
/gpio-baremetal Configure PA2 as USART2 TX alternate function on STM32F4
```

## Common Problems

| Symptom | Cause | Fix |
|---------|-------|-----|
| Pin stuck | Wrong MODER / not AF | Re-read RM pin table |
| EXTI storm | No debounce / floating input | Enable pull; debounce in software |
| AF mismatch | Wrong AFR nibble | Pin-specific AF table in RM |
| No toggle visible | Wrong port bit / LED active low | Check schematic |

## Related Skills

- `skills/baremetal/mmio-and-bit-manipulation` — BSRR/MODER masks
- `skills/baremetal/peripherals-from-datasheet` — RM pinout tables
- `skills/baremetal/uart-serial-baremetal` — AF mux for serial

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [mohitmishra786](https://github.com/mohitmishra786)
- **Source:** [mohitmishra786/low-level-dev-skills](https://github.com/mohitmishra786/low-level-dev-skills)
- **License:** MIT
- **Homepage:** https://www.lowleveldevskills.com

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-mohitmishra786-low-level-dev-skills-gpio-baremetal
- Seller: https://agentstack.voostack.com/s/mohitmishra786
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.