Fixed RTC_PRER initialization

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@15758 27425a3e-05d8-49a3-a47f-9c15f0e5edd8
2022-09-04 07:11:14 +00:00 · 2022-09-04 07:11:14 +00:00 · b21dea2d72
parent 29093a6e94
commit b21dea2d72
1 changed files with 4 additions and 1 deletions
--- a/os/hal/ports/STM32/LLD/SYSTICKv2/hal_st_lld.c
+++ b/os/hal/ports/STM32/LLD/SYSTICKv2/hal_st_lld.c
@ -109,7 +109,10 @@ void st_lld_init(void) {

  /* Activate free running Binary mode.*/
  RTC->ICSR |= RTC_ICSR_BIN_0;
-  /* Set RTC prescaler.*/
+  /* Set RTC prescaler.
+     Setting PRER has to be done as two writes. Write Sync part first
+     then Sync + Async. */
+  RTC->PRER = STM32_ST_RTC_PRER_BITS & 0x7FFF;
  RTC->PRER = STM32_ST_RTC_PRER_BITS;

  /* Exit initialization mode.*/