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blue pill: use HSE as RTC clock to be able to toogle onboard LED

This commit is contained in:
King Kévin 2018-10-28 22:44:53 +01:00
parent fc71988012
commit fd59ef5ac4
1 changed files with 6 additions and 3 deletions
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9
application.c
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@ -275,7 +275,12 @@ void main(void)
// setup RTC
printf("setup internal RTC: ");
rtc_auto_awake(RCC_LSE, 32768-1); // ensure internal RTC is on, uses the 32.678 kHz LSE, and the prescale is set to our tick speed, else update backup registers accordingly (power off the micro-controller for the change to take effect)
#if defined(BLUE_PILL) // for boards without a Low Speed External oscillator
// /!\ WARNING the blue pill LSE oscillator is affected when toggling the onboard LED, thus prefer the HSE
rtc_auto_awake(RCC_LSE, 8000000 / 128 - 1); // use High Speed External oscillator (8 MHz / 128) as RTC clock (VBAT can't be used to keep the RTC running)
#else // for boards with an precise Low Speed External oscillator
rtc_auto_awake(RCC_LSE, 32768 - 1); // ensure internal RTC is on, uses the 32.678 kHz LSE, and the prescale is set to our tick speed, else update backup registers accordingly (power off the micro-controller for the change to take effect)
#endif
rtc_interrupt_enable(RTC_SEC); // enable RTC interrupt on "seconds"
nvic_enable_irq(NVIC_RTC_IRQ); // allow the RTC to interrupt
printf("OK\n");
@ -308,9 +313,7 @@ void main(void)
while (rtc_internal_tick_flag) { // the internal RTC ticked
rtc_internal_tick_flag = false; // reset flag
action = true; // action has been performed
#if !defined(BLUE_PILL) // on the blue pill the LED is close to the 32.768 kHz oscillator and heavily influences it
led_toggle(); // toggle LED (good to indicate if main function is stuck)
#endif
}
if (action) { // go to sleep if nothing had to be done, else recheck for activity
action = false;