IRQ: Global Interrupt Control Layer

Global Interrupt Control Layer. More...

Collaboration diagram for IRQ: Global Interrupt Control Layer:

Functions
void	IRQ_UNLOCK (void)
	Enable IRQ Interrupts. More...
void	IRQ_LOCK (void)
	Disable IRQ Interrupts. More...

Detailed Description

Global Interrupt Control Layer.

---

This module provides functionality to globally enable/disable interrupts in a nested way.

Here is a simple example implementation using the CMSIS functions "__enable_irq()" and "__disable_irq()". An integer counter is used to achieve nested interrupt disabling:

// Global lock level counter value.
static volatile int g_irq_lock_ct;
 
// Global unlock all interrupts using CMSIS function "__enable_irq()".
void IRQ_UNLOCK(void)
{
    assert(g_irq_lock_ct > 0);
    if (--g_irq_lock_ct <= 0)
    {
        g_irq_lock_ct = 0;
        __enable_irq();
    }
}
 
// Global lock all interrupts using CMSIS function "__disable_irq()".
void IRQ_LOCK(void)
{
    __disable_irq();
    g_irq_lock_ct++;
}

Note

The IRQ locking mechanism is used to create atomic sections (within the scope of the AFBR-S50 API) that are very few processor instruction only. It does NOT lock interrupts for considerable amounts of time.

The IRQ_LOCK might get called multiple times. Therefore, the API expects that the IRQ_UNLOCK must be called as many times as the IRQ_LOCK was called before the interrupts are enabled.

The interrupts utilized by the AFBR-S50 API can be interrupted by other, higher prioritized interrupts, e.g. some system critical interrupts. In this case, the IRQ_LOCK/IRQ_UNLOCK mechanism can be implemented such that only the interrupts required for the AFBR-S50 API are locked. The above example is dedicated to a ARM Corex-M0 architecture, where interrupts can only disabled at a global scope. Other architectures like ARM Cortex-M4 allow selective disabling of interrupts.

Function Documentation

IRQ_LOCK()

void IRQ_LOCK

(

void

)

Disable IRQ Interrupts.

---

Disables IRQ interrupts and leaves the atomic or critical section.

Note

The IRQ_LOCK might get called multiple times. Therefore, the API expects that the IRQ_UNLOCK must be called as many times as the IRQ_LOCK was called before the interrupts are enabled.

Examples

02_advanced_example.c, 02_advanced_example_with_hal_self_test.c, 03_high_speed_example.c, and 04_multi_device_example.c.

IRQ_UNLOCK()

void IRQ_UNLOCK

(

void

)

Enable IRQ Interrupts.

---

Enables IRQ interrupts and enters an atomic or critical section.

Note

The IRQ_LOCK might get called multiple times. Therefore, the API expects that the IRQ_UNLOCK must be called as many times as the IRQ_LOCK was called before the interrupts are enabled.

Examples

02_advanced_example.c, 02_advanced_example_with_hal_self_test.c, 03_high_speed_example.c, and 04_multi_device_example.c.