A lightweight and efficient push-button driver written in C for STM32 (HAL-based).

Unlike simple polling implementations, this library uses a non-blocking, timer-driven approach, allowing the CPU to continue other tasks.
It can run on any GPIO pins and supports multiple buttons (up to 31) simultaneously.

The library is designed for:

• Projects where CPU blocking must be avoided
• Applications that require short and long press detection
• Easy portability across STM32 families

• Multi-button support (PB_CONFIG_COUNT)
• Short and long press detection
• Detect simultaneously pressed push-buttons
• Event queue with configurable size (PB_EVN_QUEUE_SIZE)
• Optional callback on button events
• Debouncing for all buttons
• Non-blocking operation via timer interrupts
• Support beep on press event
• Fully STM32 HAL compatible
• Lightweight and modular design

You can install in two ways:

Add these files to your STM32 project:

• pb.h
• pb.c
• pb_config.h

Available in the official pack repo:
👉 STM32-PACK (Not Ready)

Defines library parameters and timing values. PB_CONFIG should be fill by your pins

/* Pin definitions */ #define PB_CONFIG {.gpio = KEY_DOWN_GPIO_Port, .pin = KEY_DOWN_Pin}, \ {.gpio = KEY_UP_GPIO_Port, .pin = KEY_UP_Pin}, \ {.gpio = KEY_ENTER_GPIO_Port, .pin = KEY_ENTER_Pin}

1. GPIO Pins

   • Configure button pins as Input with Pull-Up (idle-high buttons recommended).

2. Timer

   • Use internal clock source.
   • Set prescaler to get 1us tick. e.g. for 48Mhz bus, select 48-1.
   • Enable Timer NVIC interrupt.
   • In Project Manager → Code Generator, enable Generate Peripheral initialization as a pair ".c/.h" files per peripheral.
   • In Project Manager → Advanced Settings, enable Register Callback for the timer.

#include "pb.h"

int main(void) { pb_evn_t pb_evn; pb_init(); while (1) { pb_evn = pb_read(); // Get next event from queue if (pb_evn.mask) { // 0x00000001 for short press, first key // 0x00000002 for short press, second key // 0x00000004 for short press, third key // Handle button event manually } } }

/* Optional in all cases, Can handle beep on/off by a pin or timer */ void pb_beep_on_cb(void) { // turn on buzzer pin } void pb_beep_off_cb(void) { // turn off buzzer pin } void pb_pressed_cb(pb_evn_t evn) { } int main(void) { pb_init(); while (1) { pb_loop(); } }

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Licensed under the terms in the LICENSE.