AM6421: Use EXT_REFCLK1 as time source to generate interrupts at 10uS rate

Hi Bruce,

Sorry, I am little bit confused from the above description. I have the following understanding, please confirm the same.

1. EXT_REFCLK1 is properly configured. (i.e. Pinmux settings are done correctly via Pinmux tool)?

2. Configured a timer to generate interrupt after every 10us, but only got interrupt for once?

3. Same firmware but the clock used here is HFOSC(25MHz), and everything works fine?

Regards,

Tushar

Tushar,

Your understanding is correct.  After first initializing the timer, I get a single 10uS IRQ and nothing after that when using EXT_REFCLK1(48 MHz) as the timer source clock.  I then only switch the timer source clock to HF_OSC(25MHz) and I get interrupts every 25uS as expected.  I have attached code generated by SysCfg for the timer setup with EXT_REFCLK1, along with code snips of setting up PinMux and my ISR.

A few more details:  The overall program uses FreeRTOS and is runnign on one of the R%F cores (R5FSS1-0)

The count value TwoWayTimerTick increments only once when my program executes.  If I ONLY change the clocke sourec to HFOSC, then the count increases normally.

=======================================================

Code from Sysconfig generated ti_dpl_config.c

void TimerP_isr0(void *args)
{
void DECODETIMER_TwoWayCallback(void *args);

DECODETIMER_TwoWayCallback(args);
TimerP_clearOverflowInt(gTimerBaseAddr[TWOWAY_TIMER]);
HwiP_clearInt(TWOWAY_TIMER_INT_NUM);
}

void TimerP_init()
{
TimerP_Params timerParams;
HwiP_Params timerHwiParams;
int32_t status;

/* set timer clock source */
SOC_controlModuleUnlockMMR(SOC_DOMAIN_ID_MAIN, 2);
*(volatile uint32_t*)AddrTranslateP_getLocalAddr(TWOWAY_TIMER_CLOCK_SRC_MUX_ADDR) = TWOWAY_TIMER_CLOCK_SRC_EXT_REFCLK1;
SOC_controlModuleLockMMR(SOC_DOMAIN_ID_MAIN, 2);

gTimerBaseAddr[TWOWAY_TIMER] = (uint32_t)AddrTranslateP_getLocalAddr(TWOWAY_TIMER_BASE_ADDR);

TimerP_Params_init(&timerParams);
timerParams.inputPreScaler = TWOWAY_TIMER_INPUT_PRE_SCALER;
timerParams.inputClkHz = TWOWAY_TIMER_INPUT_CLK_HZ;
timerParams.periodInNsec = TWOWAY_TIMER_NSEC_PER_TICK;
timerParams.oneshotMode = 0;
timerParams.enableOverflowInt = 1;
timerParams.enableDmaTrigger = 0;
TimerP_setup(gTimerBaseAddr[TWOWAY_TIMER], &timerParams);

HwiP_Params_init(&timerHwiParams);
timerHwiParams.intNum = TWOWAY_TIMER_INT_NUM;
timerHwiParams.callback = TimerP_isr0;
timerHwiParams.isPulse = 0;
timerHwiParams.priority = 4;
status = HwiP_construct(&gTimerHwiObj[TWOWAY_TIMER], &timerHwiParams);
DebugP_assertNoLog(status==SystemP_SUCCESS);

TimerP_start( gTimerBaseAddr[TWOWAY_TIMER] );

}

========================================================

My Pinmux code executed in main() fright after System_init();

void ExtRefClk1_config()
{
  Pinmux_PerCfg_t gPinMuxMainDomainCfg[] = {

  /* MySYSTEM1 -> EXT_REFCLK1 -> A19 */
  {  
    PIN_EXT_REFCLK1,
    PIN_MODE(0) | ((PIN_PULL_DISABLE | PIN_INPUT_ENABLE) & (~PIN_PULL_DIRECTION))
    },

    { PINMUX_END, PINMUX_END }
};

 Pinmux_config(gPinMuxMainDomainCfg, PINMUX_DOMAIN_ID_MAIN);
}

=======================================

My Interrupt service handler that simply counts interrupts:

void DECODETIMER_TwoWayCallback( void * args )
{
  TwoWayTimerTick++;
}

Hi,

Can you please confirm how are you providing external clock to the Timer module? Are all hardware connection properly done?

It looks like the source clock is not configured properly for the Timer module.

Regards,

Tushar

I agree that it seems like the clock is not configured correctly.  I checked before starting this question by using an oscilloscope to verify that the 48MHz TCXO was connected to EXT_REFCLK1 and everything seemed correct.  I have been able to verify that the 48MHz is getting to the timer by setting it to free run and looking a the count value with the debugger several times.  I'm still not sure why the interrupt is not working though.

Hi,

Thanks for the above confirmation.

Regards,

Tushar