Diff: targets/TARGET_NUVOTON/TARGET_M451/rtc_api.c

Revision:

172:7d866c31b3c5

Parent:

167:e84263d55307

Child:

176:447f873cad2f

--- a/targets/TARGET_NUVOTON/TARGET_M451/rtc_api.c	Wed Aug 16 18:27:13 2017 +0100
+++ b/targets/TARGET_NUVOTON/TARGET_M451/rtc_api.c	Thu Aug 31 17:27:04 2017 +0100
@@ -26,31 +26,33 @@
 
 #define YEAR0       1900
 //#define EPOCH_YR    1970
-static int rtc_inited = 0;
 
 static const struct nu_modinit_s rtc_modinit = {RTC_0, RTC_MODULE, 0, 0, 0, RTC_IRQn, NULL};
 
 void rtc_init(void)
 {
-    if (rtc_inited) {
+    if (rtc_isenabled()) {
         return;
     }
-    rtc_inited = 1;
-    
-    // Enable IP clock
-    CLK_EnableModuleClock(rtc_modinit.clkidx);
     
     RTC_Open(NULL);
 }
 
 void rtc_free(void)
 {
-    // FIXME
+    // N/A
 }
 
 int rtc_isenabled(void)
 {
-    return rtc_inited;
+    // NOTE: To access (RTC) registers, clock must be enabled first.
+    if (! (CLK->APBCLK0 & CLK_APBCLK0_RTCCKEN_Msk)) {
+        // Enable IP clock
+        CLK_EnableModuleClock(rtc_modinit.clkidx);
+    }
+    
+    // NOTE: Check RTC Init Active flag to support crossing reset cycle.
+    return  !! (RTC->INIT & RTC_INIT_ACTIVE_Msk);
 }
 
 /*
@@ -68,7 +70,9 @@
 
 time_t rtc_read(void)
 {
-    if (! rtc_inited) {
+    // NOTE: After boot, RTC time registers are not synced immediately, about 1 sec latency.
+    //       RTC time got (through RTC_GetDateAndTime()) in this sec would be last-synced and incorrect.
+    if (! rtc_isenabled()) {
         rtc_init();
     }
     
@@ -94,7 +98,7 @@
 
 void rtc_write(time_t t)
 {
-    if (! rtc_inited) {
+    if (! rtc_isenabled()) {
         rtc_init();
     }