Hi,
I'm trying to configure GMT timer.
The problem is that, result frequency is different than the one i set.
I have following init function:
void gtm_timers_initialization(void){
boolean interruptState = IfxCpu_disableInterrupts();
/* set Gtm clock frequency */
float32 gtm_frequency = IfxGtm_Cmu_getModuleFrequency(gtm);
IfxGtm_enable(gtm);
IfxGtm_Cmu_setGclkFrequency(gtm, gtm_frequency);
IfxGtm_Tom_Timer_Config timerConfig;
IfxGtm_Tom_Timer_initConfig(&timerConfig, gtm);
/* power switch timer */
timerConfig.base.frequency = 100; //100Hz
timerConfig.base.minResolution = (1.0/timerConfig.base.frequency)
/TIMER_RESOLUTION_DIVIDER;
timerConfig.base.isrProvider = ISR_PROVIDER(INTERRUPT_TIMER_10MS);
timerConfig.base.isrPriority = ISR_PRIORITY(INTERRUPT_TIMER_10MS);
timerConfig.base.trigger.enabled = FALSE;
timerConfig.tom = IfxGtm_Tom_0;
timerConfig.timerChannel = IfxGtm_Tom_Ch_0;
timerConfig.clock = IfxGtm_Tom_Ch_ClkSrc_cmuFxclk0;
IfxGtm_Tom_Timer_init(&tom_timer, &timerConfig);
IfxCpu_restoreInterrupts(interruptState);
IfxGtm_Cmu_enableClocks(gtm,
IFXGTM_CMU_CLKEN_FXCLK | IFXGTM_CMU_CLKEN_CLK0);
IfxGtm_Tom_Timer_run(&tom_timer);
}
I also use timer interrupts.
IFX_INTERRUPT(ISR_Timer_10ms, 0, ISR_PRIORITY_TIMER_10MS){
if(switch_timer % 2 == 0){
switch_on_pin();
}else{
switch_off_pin();
}
switch_timer++;
}The problem is, that the frequency of setting/resenting is complettly different than the one i set.
if I set timerConfig.base.frequency = 100 (Hz) which is 10 ms period, interrupt is firing in 450 us period (2.2 kHz).
If I set timerConfig.base.frequency = 1000(Hz) which is 1ms, interrupt is firing in 45 us period (22.2 kHz).
As source I use PLL that is ramped-up to 133.33 MHz, f_source = 133.33 MHz.
f_GTM = f_ source
Why GTM timer is setting completely different frequency than those configured?
I work on Tc222L
