ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

[NUCLEO_F103RB] Add LSE configuration for RTC

pull/283/head
bcostm 2014-04-29 11:02:11 +02:00 committed by Toyomasa Watarai
parent da8db27ea4
commit 6f2c83a0ff
2 changed files with 41 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
libraries/mbed/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F103RB/stm32f10x.h
View File

@ -147,6 +147,10 @@
#define HSI_VALUE ((uint32_t)8000000) /*!< Value of the Internal oscillator in Hz*/
#endif /* HSI_VALUE */
#if !defined (LSE_VALUE)
#define LSE_VALUE ((uint32_t)32768) /*!< Value of the External Low Speed oscillator in Hz */
#endif
/**
* @brief STM32F10x Standard Peripheral Library version number
*/

52
libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F103RB/rtc_api.c
View File

@ -29,27 +29,49 @@
*/
#include "rtc_api.h"
#if DEVICE_RTC
#include "wait_api.h"
#define LSE_STARTUP_TIMEOUT ((uint16_t)700) // delay in ms
static int rtc_inited = 0;
void rtc_init(void) {
uint32_t StartUpCounter = 0;
uint32_t LSEStatus = 0;
uint32_t rtc_freq = 0;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE); // Enable PWR and Backup clock
PWR_BackupAccessCmd(ENABLE); // Allow access to Backup Domain
BKP_DeInit(); // Reset Backup Domain
// Uncomment these lines if you use the LSE
// Enable LSE and wait till it's ready
//RCC_LSEConfig(RCC_LSE_ON);
//while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) {}
//RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE); // Select LSE as RTC Clock Source
// Uncomment these lines if you use the LSI
// Enable LSI and wait till it's ready
RCC_LSICmd(ENABLE);
while (RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET) {}
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI); // Select LSI as RTC Clock Source
// Enable LSE clock
RCC_LSEConfig(RCC_LSE_ON);
// Wait till LSE is ready
do {
LSEStatus = RCC_GetFlagStatus(RCC_FLAG_LSERDY);
wait_ms(1);
StartUpCounter++;
} while ((LSEStatus == 0) && (StartUpCounter <= LSE_STARTUP_TIMEOUT));
if (StartUpCounter > LSE_STARTUP_TIMEOUT) {
// The LSE has not started, use LSI instead.
// The RTC Clock may vary due to LSI frequency dispersion.
RCC_LSEConfig(RCC_LSE_OFF);
RCC_LSICmd(ENABLE); // Enable LSI
while (RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET) {} // Wait until ready
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI); // Select the RTC Clock Source
rtc_freq = 40000; // [TODO] To be measured precisely using a timer input capture
} else {
// The LSE has correctly started
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE); // Select the RTC Clock Source
rtc_freq = LSE_VALUE;
}
RCC_RTCCLKCmd(ENABLE); // Enable RTC Clock
RTC_WaitForSynchro(); // Wait for RTC registers synchronization
@ -57,9 +79,7 @@ void rtc_init(void) {
RTC_WaitForLastTask(); // Wait until last write operation on RTC registers has finished
// Set RTC period to 1 sec
// For LSE: prescaler = RTCCLK/RTC period = 32768Hz/1Hz = 32768
// For LSI: prescaler = RTCCLK/RTC period = 40000Hz/1Hz = 40000
RTC_SetPrescaler(39999);
RTC_SetPrescaler(rtc_freq - 1);
RTC_WaitForLastTask(); // Wait until last write operation on RTC registers has finished
@ -84,3 +104,5 @@ void rtc_write(time_t t) {
RTC_SetCounter(t); // Change the current time
RTC_WaitForLastTask(); // Wait until last write operation on RTC registers has finished
}
#endif