HW Interrupts

Table of Contents

• Features Supported
• Features NOT Supported
• Important Usage Guidelines
• Example Usage
• API

Attention

See also FreeRTOS, NO RTOS for list of CPU specific supported and unsupported features.

Features Supported

• Register a interrupt callback to a specific CPU number
• Ability to pass user specific argument to the interrupt callback
• Enable, disable, restore and clear specific CPU interrupts
• Enable, disable, restore global CPU interrupt
• For ARM R5,
  • Ability to specify interrupt as FIQ or IRQ, level or pulse
  • Ability to specify interrupt priority

Features NOT Supported

See also FreeRTOS, NO RTOS for list of unsupported features.

Important Usage Guidelines

• For ARM R5,
  • TI VIM is the interrupt controller that is supported.
  • HwiP_disable, HwiP_restore, HwiP_enable only affect state of IRQ. FIQ state is not changed
  • Refer ARMv7-R Architecture reference manual and SOC TRM for more details.
• On AM62AX,

  CPU type	Valid interrupt numbers	Valid interrupt priorities
  R5F	0 .. 511	0 (highest) .. 15 (lowest)

• On C75,
  • The C75 CPU supports 64 interrupts.
  • The CLEC event ID can be mapped to any of C75 interrupts.
  • If you are configuring software interrupt, then set eventId to HWIP_INVALID_EVENT_ID.
  • While mapping CLEC event ID to interrupt number, refer the below table and avoid overlapping interrupts.

    Module	Interrupt number used
    EQEP	5 .. 7
    TIMER	8 .. 15
    I2C	16 .. 20
    GPIO	21
    UART	22 .. 30
    ECAP	25 .. 27
    UDMA	32 .. 48
    EPWM	49 .. 51
    MCASP	53 .. 58
    IPC	59 .. 62
    MCSPI	1, 2, 31, 52, 63

Example Usage

Include the below file to access the APIs,

#include <stdio.h>
#include <kernel/dpl/HwiP.h>

Example ISR,

void myISR(void *args)
{
    /* my ISR */
}

Example to register a ISR for CPU interrupt 10,

    HwiP_Params hwiParams;
    HwiP_Object hwiObj;
 
    HwiP_Params_init(&hwiParams);
    /* for R5F, interrupt #10 at VIM */
    hwiParams.intNum = 10;
    /* for M4F, external interrupt #10 at NVIC is
       16 internal interrupts + external interrupt number at NVIC
       i.e hwiParams.intNum = 16 + 10;
     */
    /* for C75, CLEC event ID can be mapped to any of the internal interrupt number
       set both event ID and interrupt number
       to configure harware clec event #10
           hwiParams.eventId = 10;
           hwiParams.intNum = 31;
       to configure software interrupt #31
           hwiParams.eventId = HWIP_INVALID_EVENT_ID;
           hwiParams.intNum = 31;
 
     */
    hwiParams.callback = myISR;
    hwiParams.args = NULL;
 
    HwiP_construct(&hwiObj, &hwiParams);

Example to disable and restore interrupts across a crtical section

    uintptr_t oldIntState;
 
    oldIntState = HwiP_disable();
 
    /* critical section */
 
    HwiP_restore(oldIntState);

API

APIs for HW Interrupts