1 files changed, 93 insertions, 0 deletions
diff --git a/stm/rtc.c b/stm/rtc.c
new file mode 100644
index 0000000000..9adfd3a7ad
--- /dev/null
+++ b/stm/rtc.c
@@ -0,0 +1,93 @@
+#include <stdio.h>
+#include <stm32f4xx.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "mpconfigport.h"
+#include "qstr.h"
+#include "obj.h"
+#include "rtc.h"
+
+void rtc_init(void) {
+    uint32_t rtc_clksrc;
+    uint32_t timeout = 1000000;
+
+    /* Enable the PWR clock */
+    RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
+
+    /* Allow access to RTC */
+    PWR_BackupAccessCmd(ENABLE);
+
+    /* Enable the LSE OSC */
+    RCC_LSEConfig(RCC_LSE_ON);
+
+    /* Wait till LSE is ready */
+    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 */
+    RCC_RTCCLKConfig(rtc_clksrc);
+
+    /* Note: LSI is around (32KHz), these dividers should work either way */
+    /* ck_spre(1Hz) = RTCCLK(LSE) /(uwAsynchPrediv + 1)*(uwSynchPrediv + 1)*/
+    uint32_t uwSynchPrediv = 0xFF;
+    uint32_t uwAsynchPrediv = 0x7F;
+
+    /* Enable the RTC Clock */
+    RCC_RTCCLKCmd(ENABLE);
+
+    /* Wait for RTC APB registers synchronisation */
+    RTC_WaitForSynchro();
+
+    /* Configure the RTC data register and RTC prescaler */
+    RTC_InitTypeDef RTC_InitStructure;
+    RTC_InitStructure.RTC_AsynchPrediv = uwAsynchPrediv;
+    RTC_InitStructure.RTC_SynchPrediv = uwSynchPrediv;
+    RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;
+    RTC_Init(&RTC_InitStructure);
+
+    // Set the date (BCD)
+    RTC_DateTypeDef RTC_DateStructure;
+    RTC_DateStructure.RTC_Year = 0x13;
+    RTC_DateStructure.RTC_Month = RTC_Month_October;
+    RTC_DateStructure.RTC_Date = 0x26;
+    RTC_DateStructure.RTC_WeekDay = RTC_Weekday_Saturday;
+    RTC_SetDate(RTC_Format_BCD, &RTC_DateStructure);
+
+    // Set the time (BCD)
+    RTC_TimeTypeDef RTC_TimeStructure;
+    RTC_TimeStructure.RTC_H12     = RTC_H12_AM;
+    RTC_TimeStructure.RTC_Hours   = 0x01;
+    RTC_TimeStructure.RTC_Minutes = 0x53;
+    RTC_TimeStructure.RTC_Seconds = 0x00;
+    RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure);
+
+    // Indicator for the RTC configuration
+    //RTC_WriteBackupRegister(RTC_BKP_DR0, 0x32F2);
+}
+
+/******************************************************************************/
+/* Micro Python bindings                                                      */
+
+mp_obj_t pyb_rtc_read(void) {
+    RTC_TimeTypeDef RTC_TimeStructure;
+    RTC_GetTime(RTC_Format_BIN, &RTC_TimeStructure);
+    printf("%02d:%02d:%02d\n", RTC_TimeStructure.RTC_Hours, RTC_TimeStructure.RTC_Minutes, RTC_TimeStructure.RTC_Seconds);
+    return mp_const_none;
+}