//[[ Most of the system-timer functionality is part of the hal-library
// This functionality is kept public because it depends on configuration
// options defined in the BOARD_HEADER. Only for the full HAL, though. In
// the minimal HAL if the user has to supply the two ifdefs they do so
// in whatever manner they choose.
//]]
uint16_t halInternalStartSystemTimer(void)
{
//Since the SleepTMR is the only timer maintained during deep sleep, it is
//used as the System Timer (RTC). We maintain a 32 bit hardware timer
//configured for a tick value time of 1024 ticks/second (0.9765625 ms/tick)
//using either the 10 kHz internal SlowRC clock divided and calibrated to
//1024 Hz or the external 32.768 kHz crystal divided to 1024 Hz.
//With a tick time of ~1ms, this 32bit timer will wrap after ~48.5 days.
//disable top-level interrupt while configuring
INT_CFGCLR = INT_SLEEPTMR;
if (useOsc32k > OSC32K_DISABLE) {
if (useOsc32k == OSC32K_DIGITAL) {
//Disable both OSC32K and SLOWRC if using external digital clock input
SLEEPTMR_CLKEN = 0;
} else { // OSC32K_CRYSTAL || OSC32K_SINE_1V
//Enable the 32kHz XTAL (and disable SlowRC since it is not needed)
SLEEPTMR_CLKEN = SLEEPTMR_CLK32KEN;
}
//Sleep timer configuration is the same for crystal and external clock
SLEEPTMR_CFG = (SLEEPTMR_ENABLE | //enable TMR
(0 << SLEEPTMR_DBGPAUSE_BIT)| //TMR not paused when halted
(5 << SLEEPTMR_CLKDIV_BIT) | //divide down to 1024Hz
(1 << SLEEPTMR_CLKSEL_BIT)) ; //select CLK32K external clock
halCommonDelayMilliseconds(OSC32K_STARTUP_DELAY_MS);
} else {
//Enable the SlowRC (and disable 32kHz XTAL since it is not needed)
SLEEPTMR_CLKEN = SLEEPTMR_CLK10KEN;
SLEEPTMR_CFG = (SLEEPTMR_ENABLE | //enable TMR
(0 << SLEEPTMR_DBGPAUSE_BIT)| //TMR not paused when halted
(0 << SLEEPTMR_CLKDIV_BIT) | //already 1024Hz
(0 << SLEEPTMR_CLKSEL_BIT)) ; //select CLK1K internal SlowRC
#ifndef DISABLE_RC_CALIBRATION
halInternalCalibrateSlowRc(); //calibrate SlowRC to 1024Hz
#endif//DISABLE_RC_CALIBRATION
}
//clear out any stale interrupts
INT_SLEEPTMRFLAG = (INT_SLEEPTMRWRAP | INT_SLEEPTMRCMPA | INT_SLEEPTMRCMPB);
//turn off second level interrupts. they will be enabled elsewhere as needed
INT_SLEEPTMRCFG = INT_SLEEPTMRCFG_RESET;
//enable top-level interrupt
INT_CFGSET = INT_SLEEPTMR;
return 0;
}
/**
* @brief Starts system timer
* @param None
* @retval Return unsigned value
*/
uint16_t halInternalStartSystemTimer(void)
{
/* Since the SleepTMR is the only timer maintained during deep sleep, it is
* used as the System Timer (RTC). We maintain a 32 bit hardware timer
* configured for a tick value time of 1024 ticks/second (0.9765625 ms/tick)
* using either the 10 kHz internal SlowRC clock divided and calibrated to
* 1024 Hz or the external 32.768 kHz crystal divided to 1024 Hz.
* With a tick time of ~1ms, this 32bit timer will wrap after ~48.5 days. */
/* disable top-level interrupt while configuring */
NVIC->ICER[0] = NVIC_IxxR_SLEEPTMR;
#ifdef ENABLE_OSC32K
#ifdef DIGITAL_OSC32_EXT
/* Disable both OSC32K and SLOWRC if using external digital clock input */
CLK->SLEEPCR = 0;
#else /*!DIGITAL_OSC32_EXT */
/* Enable the 32kHz XTAL (and disable SlowRC since it is not needed) */
CLK->SLEEPCR = CLK_SLEEPCR_LSEEN;
#endif
/* Sleep timer configuration is the same for crystal and external clock */
SLPTMR->CR = (SLPTMR_CR_EN | /* enable TMR */
(0 << 10)| /* TMR not paused when halted */
(5 << 4) | /* divide down to 1024Hz */
(1 << 0)) ; /* select XTAL */
#else /* !ENABLE_OSC32K */
/* Enable the SlowRC (and disable 32kHz XTAL since it is not needed) */
CLK->SLEEPCR = CLK_SLEEPCR_LSI10KEN;
SLPTMR->CR = (SLPTMR_CR_EN | /* enable TMR */
(0 << 10)| /* TMR not paused when halted */
(0 << 4) | /* already 1024Hz */
(0 << 0)) ; /* select SlowRC */
#ifndef DISABLE_RC_CALIBRATION
halInternalCalibrateSlowRc(); /* calibrate SlowRC to 1024Hz */
#endif /* DISABLE_RC_CALIBRATION */
#endif /*ENABLE_OSC32K */
/* clear out any stale interrupts */
SLPTMR->ISR = (SLPTMR_IER_WRAP | SLPTMR_IER_CMPA | SLPTMR_IER_CMPB);
/* turn off second level interrupts. they will be enabled elsewhere as needed */
SLPTMR->IER = 0x00;
/* enable top-level interrupt */
NVIC->ISER[0] = NVIC_IxxR_SLEEPTMR;
return 0;
}
