Kinetis Microcontrollers中的主题 Re: K70-TWR RTC

K70-TWR RTC

chrislynch — Mon, 04 Mar 2013 09:50:40 GMT

Hi,

I am having issues getting the RTC->TSR & RTC->TPR registers to increment on a K70-TWR board i just received.

I have had no problem getting a K60-TWR RTC to work correctly and the code below is identical (apart from enabling RTC->IER), I am using Keil uVision.

void rtc_init(void)

{

unsigned int i;

/*enable the clock to SRTC module register space*/

SIM->SCGC6 |= SIM_SCGC6_RTC_MASK;

/*Only VBAT_POR has an effect on the SRTC, RESET to the part does not, so you must manually reset the SRTC to make sure everything is in a known state*/

/*clear the software reset bit*/

RTC->CR = RTC_CR_SWR_MASK;

RTC->CR &= ~RTC_CR_SWR_MASK;

/*Enable the oscillator*/

RTC->CR |= RTC_CR_OSCE_MASK | RTC_CR_SC16P_MASK;

/*Wait to all the 32 kHz to stabilize, refer to the crystal startup time in the crystal datasheet*/

// for(i=0;i<0x600000;i++);

for(i=0;i<0x6000000;i++);//120MHz clock, so 838ms long delay for test

/*Set time compensation parameters*/

RTC->TCR = RTC_TCR_CIR(0) | RTC_TCR_TCR(0);

/*Configure the timer seconds and alarm registers*/

RTC->TSR = 0x0F;

RTC->TAR = 0xFFFFFFFF;

/*Enable Interrupts*/

RTC->IER= RTC_IER_TIIE_MASK | RTC_IER_TOIE_MASK;

/*Enable NVIC RTC interrupt*/

NVIC_EnableIRQ(RTC_IRQn);

/*Enable the counter*/

RTC->SR |= RTC_SR_TCE_MASK;

}

void RTC_IRQHandler(void)

{

if((RTC->SR & RTC_SR_TIF_MASK)== 0x01)

{

//printf("SRTC time invalid interrupt entered...\r\n");

RTC->SR &= 0x07; //clear TCE, or RTC_TSR can not be written

RTC->TSR = 0x00000000; //clear TIF

}

else if((RTC->SR & RTC_SR_TOF_MASK) == 0x02)

{

//printf("SRTC time overflow interrupt entered...\r\n");

RTC->SR &= 0x07; //clear TCE, or RTC_TSR can not be written

RTC->TSR = 0x00000000; //clear TOF

}

else if((RTC->SR & RTC_SR_TAF_MASK) == 0x04)

{

// printf("SRTC alarm interrupt entered...\r\n");

// printf("Time Seconds Register value is: %i\n", RTC_TSR);

RTC->TAR += 1;// Write new alarm value, to generate an alarm every second add 1

}

else

{

//printf("No valid Flag was set!\n");

}

return;

}

Re: K70-TWR RTC

chrislynch — Mon, 04 Mar 2013 10:53:28 GMT

I also found that RTC_IRQHandler is entered after the rtc_init function, when it enters the handler the RTC->SR value is 0x10.. Consequently it enters the last else statement of the interrupt handler. Im unsure why it enters the handler at all as the RTC->SR value is correct with no interrupt flags set.

Re: K70-TWR RTC

chrislynch — Mon, 04 Mar 2013 11:01:15 GMT

I just scoped the external xtal and it is not oscillating, it is on the K60 with the same code. Maybe its a dud crystal?

Re: K70-TWR RTC

chrislynch — Mon, 04 Mar 2013 11:11:37 GMT

Agghhhhh i just swapped the crystal from my K60 to the K70 board and it worked. I just wasted my weekend :smileysad:.

Im disappointed in Freescale as its a brand new TWR board.

Re: K70-TWR RTC

chrislynch — Mon, 04 Mar 2013 11:27:10 GMT

Just put the suspect crystal on the K60 for a test and it works, I will have to put it down to a bad joint as one of the crystal pins came away from its pad when i was heating the body of the crystal (also soldered to the pcb). So if anyone else has a similar experience try re-soldering the crystal joints.

Re: K70-TWR RTC

Monica — Tue, 05 Mar 2013 22:21:37 GMT

Chris,

I'm sorry you're having inconveniences with our products.

However, your feedback here is very important and I really appreciate you're sharing it over.

Thanks and best regards.

Monica.