Quick Start Guide for the MEGARF ext int Driver

This is the quick start guide for the Global interrupt management , with step-by-step instructions on how to configure and use the driver for a specific use case.

The code examples can be copied into e.g the main application loop or any other function that will need to control the external interrupt.

Use cases

• External Interrupt
• external pin change interrupt

External Interrupt

This use case will prepare a external interrupt pin to trigger an interrupt when the there is a change in pin state. The interrupt is handled by a cutomisable callback function. We will setup the external interrupt in this mode:

• Enable the interrupt for falling edge(for example)
• Use the system clock as clock source
• Enable the Global Interrupt

Setup steps

Prequisites

For the setup code of this use case to work, the following must be added to the project:

• Global Interrupt Management
• Clock Management

Example code

Add a callback function that will be executed when the interrupt trigger.

static void ext_int_callback(void)
{
    // User code to execute when the interrupt occurs here
}

Add to, e.g., the main loop in the application C-file:

sysclk_init();
ext_int_init(EXT_INT0, IOPORT_SENSE_FALLING);
ext_int_set_interrupt_callback(EXT_INT0, ext_int_callback);
cpu_irq_enable();

Workflow

1. Enable the clock system:

   • sysclk_init(); 

2. Enable External Interrupt INT0

   • ext_int_init(EXT_INT0, IOPORT_SENSE_FALLING); 

3. Set the callback function for interrupt

   • ext_int_set_interrupt_callback(EXT_INT0, ext_int_callback); 

     Warning

     This function requires that the ext_int_callback function is defined

4. Enable interrupts:

   • cpu_irq_enable(); 

Usage steps

• None. The code written in the call back function will execute each time external interrupt pin state changes to falling edge.

external pin change interrupt

This use case will prepare a external pin change interrupt to trigger an interrupt when the there is a change in pin state. The interrupt is handled by a cutomisable callback function.

We will setup the external interrupt in this mode:

• Enable the pin change interrupt
• Use the system clock as clock source
• Enable the Global Interrupt

Setup steps

Prequisites

For the setup code of this use case to work, the following must be added to the project:

• Global Interrupt Management
• Clock Management

Example code

Add a callback function that will be executed when the interrupt trigger.

static void ext_pcint_callback(void)
{
    // User code to execute when the interrupt occurs here
}

Add to, e.g., the main loop in the application C-file:

sysclk_init();
ext_int_pcint_init(PC_INT8);
ext_int_set_interrupt_callback(PC_INT8, ext_pcint_callback);
cpu_irq_enable();

Workflow

1. Enable the clock system:

   • sysclk_init(); 

2. Enable External Interrupt INT0

   • ext_int_pcint_init(PC_INT8); 

3. Set the callback function for interrupt

   • ext_int_set_interrupt_callback(PC_INT8, ext_pcint_callback); 

     Warning

     This function requires that the ext_pcint_callback function is defined

4. Enable interrupts:

   • cpu_irq_enable(); 

Usage steps

• None. The code written in the call back function will execute each time external interrupt pin state changes.