RC5-on-STM32-without-timer

This project is an STM32 implementation of the Arduino RC5 IR Remote Library, designed for STM32 Nucleo-F411RE using STM32CubeIDE.

The project reads RC5 protocol signals using external interrupts (EXTI) in a fully non-blocking manner. It includes a custom micros() function that emulates Arduino’s micros() functionality, without requiring an external hardware timer.

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📦 Project Features

• ✅ Non-blocking RC5 signal decoding via EXTI interrupts
• ✅ RC5 protocol implementation based on the Arduino library logic
• ✅ Custom micros() function using only SysTick
• ✅ No external libraries or hardware timers required
• ✅ Developed for STM32 Nucleo-F411RE in STM32CubeIDE

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🔧 How to Integrate in Your Own Project

To integrate this RC5 decoder into your own STM32 project:

1. 🧩 Configure the IR Input Pin

• Select a GPIO pin connected to the IR receiver (e.g. PA0).
• Set the GPIO mode to GPIO_EXTI.
• Enable Interrupt trigger for Both rising and falling edges.

2. 🔔 Enable EXTI in NVIC

• In STM32CubeMX or STM32CubeIDE:
  • Go to the NVIC tab
  • Enable the corresponding EXTI interrupt line (e.g. EXTI0 for pin PA0).

3. 🧠 Copy Required Code

User Code 0 section (in main.c)

Copy:

• micros() function
• All related global variables

User Code 4 section (in stm32f4xx_it.c)

Copy:

• EXTIx_IRQHandler() implementation (e.g., EXTI0_IRQHandler)
• RC5 decoding logic based on pulse timing

Ensure that the interrupt handler matches your selected GPIO pin and EXTI line.

4. Change the pin label

• in 'RC5read1' function change the pin label in 'HAL_GPIO_ReadPin' to your pin label. Here, pin has label 'IR_IN'.

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