run watch at 4 MHz unless USB is enabled

This commit is contained in:
Joey Castillo 2021-08-30 17:35:47 -04:00
parent eb3d9b26cb
commit fbd9ae4b67
4 changed files with 17 additions and 6 deletions

View file

@ -147,7 +147,7 @@
// <i> This defines the oscillator frequency (Mhz) // <i> This defines the oscillator frequency (Mhz)
// <id> osc16m_freq // <id> osc16m_freq
#ifndef CONF_OSC16M_FSEL #ifndef CONF_OSC16M_FSEL
#define CONF_OSC16M_FSEL OSCCTRL_OSC16MCTRL_FSEL_8_Val #define CONF_OSC16M_FSEL OSCCTRL_OSC16MCTRL_FSEL_4_Val
#endif #endif
// <q> Oscillator Calibration Control // <q> Oscillator Calibration Control

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@ -61,7 +61,7 @@
* \brief CPU's Clock frequency * \brief CPU's Clock frequency
*/ */
#ifndef CONF_CPU_FREQUENCY #ifndef CONF_CPU_FREQUENCY
#define CONF_CPU_FREQUENCY 8000000 #define CONF_CPU_FREQUENCY 4000000
#endif #endif
// <y> RTC Clock Source // <y> RTC Clock Source

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@ -167,7 +167,8 @@ static inline uint32_t _get_cycles_for_us_internal(const uint16_t us, const uint
*/ */
uint32_t _get_cycles_for_us(const uint16_t us) uint32_t _get_cycles_for_us(const uint16_t us)
{ {
return _get_cycles_for_us_internal(us, CONF_CPU_FREQUENCY, CPU_FREQ_POWER); int32_t freq = hri_usbdevice_get_CTRLA_ENABLE_bit(USB) ? 8000000 : 4000000;
return _get_cycles_for_us_internal(us, freq, CPU_FREQ_POWER);
} }
/** /**
@ -196,5 +197,6 @@ static inline uint32_t _get_cycles_for_ms_internal(const uint16_t ms, const uint
*/ */
uint32_t _get_cycles_for_ms(const uint16_t ms) uint32_t _get_cycles_for_ms(const uint16_t ms)
{ {
return _get_cycles_for_ms_internal(ms, CONF_CPU_FREQUENCY, CPU_FREQ_POWER); int32_t freq = hri_usbdevice_get_CTRLA_ENABLE_bit(USB) ? 8000000 : 4000000;
return _get_cycles_for_ms_internal(ms, freq, CPU_FREQ_POWER);
} }

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@ -54,8 +54,14 @@ void _watch_enable_tcc() {
hri_tcc_wait_for_sync(TCC0, TCC_SYNCBUSY_ENABLE); hri_tcc_wait_for_sync(TCC0, TCC_SYNCBUSY_ENABLE);
hri_tcc_write_CTRLA_reg(TCC0, TCC_CTRLA_SWRST); hri_tcc_write_CTRLA_reg(TCC0, TCC_CTRLA_SWRST);
hri_tcc_wait_for_sync(TCC0, TCC_SYNCBUSY_SWRST); hri_tcc_wait_for_sync(TCC0, TCC_SYNCBUSY_SWRST);
// have prescaler divide our 8 MHz clock down to 1 MHz. // divide the clock down to 1 MHz
hri_tcc_write_CTRLA_reg(TCC0, TCC_CTRLA_PRESCALER_DIV8); if (hri_usbdevice_get_CTRLA_ENABLE_bit(USB)) {
// if USB is enabled, we are running an 8 MHz clock.
hri_tcc_write_CTRLA_reg(TCC0, TCC_CTRLA_PRESCALER_DIV8);
} else {
// otherwise it's 4 Mhz.
hri_tcc_write_CTRLA_reg(TCC0, TCC_CTRLA_PRESCALER_DIV4);
}
// We're going to use normal PWM mode, which means period is controlled by PER, and duty cycle is controlled by // We're going to use normal PWM mode, which means period is controlled by PER, and duty cycle is controlled by
// each compare channel's value: // each compare channel's value:
// * Buzzer tones are set by setting PER to the desired period for a given frequency, and CC[1] to half of that // * Buzzer tones are set by setting PER to the desired period for a given frequency, and CC[1] to half of that
@ -98,6 +104,9 @@ void _watch_enable_usb() {
// disable USB, just in case. // disable USB, just in case.
hri_usb_clear_CTRLA_ENABLE_bit(USB); hri_usb_clear_CTRLA_ENABLE_bit(USB);
// bump clock up to 8 MHz
hri_oscctrl_write_OSC16MCTRL_FSEL_bf(OSCCTRL, OSCCTRL_OSC16MCTRL_FSEL_8_Val);
// reset flags and disable DFLL // reset flags and disable DFLL
OSCCTRL->INTFLAG.reg = OSCCTRL_INTFLAG_DFLLRDY; OSCCTRL->INTFLAG.reg = OSCCTRL_INTFLAG_DFLLRDY;
OSCCTRL->DFLLCTRL.reg = 0; OSCCTRL->DFLLCTRL.reg = 0;