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Merge pull request #112 from iabdalkader/master 

Use LSI OSC for RTC clock when LSE is not detected
This commit is contained in:
Damien George 2014-01-08 07:34:38 -08:00
parent 9193f89296 5df3d47ee0
commit ea9e441a75
1 changed files with 23 additions and 2 deletions
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25
stm/main.c
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@ -585,6 +585,9 @@ mp_obj_t pyb_hid_send_report(mp_obj_t arg) {
} }
static void rtc_init(void) { static void rtc_init(void) {
uint32_t rtc_clksrc;
uint32_t timeout =10000;
/* Enable the PWR clock */ /* Enable the PWR clock */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE); RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
@ -595,11 +598,29 @@ static void rtc_init(void) {
RCC_LSEConfig(RCC_LSE_ON); RCC_LSEConfig(RCC_LSE_ON);
/* Wait till LSE is ready */ /* Wait till LSE is ready */
while(RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) { while((RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) && (--timeout > 0)) {
}
/* If LSE timed out, use LSI instead */
if (timeout == 0) {
/* Enable the LSI OSC */
RCC_LSICmd(ENABLE);
/* Wait till LSI is ready */
while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET) {
}
/* Use LSI as the RTC Clock Source */
rtc_clksrc = RCC_RTCCLKSource_LSI;
} else {
/* Use LSE as the RTC Clock Source */
rtc_clksrc = RCC_RTCCLKSource_LSE;
} }
/* Select the RTC Clock Source */ /* Select the RTC Clock Source */
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE); RCC_RTCCLKConfig(rtc_clksrc);
/* Note: LSI is around (32KHz), these dividers should work either way */
/* ck_spre(1Hz) = RTCCLK(LSE) /(uwAsynchPrediv + 1)*(uwSynchPrediv + 1)*/ /* ck_spre(1Hz) = RTCCLK(LSE) /(uwAsynchPrediv + 1)*(uwSynchPrediv + 1)*/
uint32_t uwSynchPrediv = 0xFF; uint32_t uwSynchPrediv = 0xFF;
uint32_t uwAsynchPrediv = 0x7F; uint32_t uwAsynchPrediv = 0x7F;