diff options
| -rw-r--r-- | ports/nrf/common-hal/rtc/RTC.c | 29 | ||||
| -rw-r--r-- | ports/nrf/common-hal/rtc/RTC.h | 1 |
2 files changed, 27 insertions, 3 deletions
diff --git a/ports/nrf/common-hal/rtc/RTC.c b/ports/nrf/common-hal/rtc/RTC.c index 9f56f2f0d..06345f589 100644 --- a/ports/nrf/common-hal/rtc/RTC.c +++ b/ports/nrf/common-hal/rtc/RTC.c @@ -34,11 +34,28 @@ #include "supervisor/shared/translate.h" // This is the time in seconds since 2000 that the RTC was started. -static uint32_t rtc_offset = 0; +__attribute__((section(".uninitialized"))) static uint32_t rtc_offset[3]; + +// These values are placed before and after the current RTC count. They are +// used to determine if the RTC count is valid. These randomly-generated values +// will be set when the RTC value is set in order to mark the RTC as valid. If +// the system crashes or reboots, these values will remain undisturbed and the +// RTC offset will remain valid. +// +// If Circuit Python is updated or these symbols shift around, the prefix and +// suffix will no longer match, and the time will no longer be valid. +#define RTC_OFFSET_CHECK_PREFIX 0x25ea7e2a +#define RTC_OFFSET_CHECK_SUFFIX 0x2b80b69e + +void common_hal_rtc_init(void) { + // If the prefix and suffix are not valid, zero-initialize the RTC offset. + if ((rtc_offset[0] != RTC_OFFSET_CHECK_PREFIX) || (rtc_offset[2] != RTC_OFFSET_CHECK_SUFFIX)) + rtc_offset[1] = 0; +} void common_hal_rtc_get_time(timeutils_struct_time_t *tm) { uint64_t ticks_s = port_get_raw_ticks(NULL) / 1024; - timeutils_seconds_since_2000_to_struct_time(rtc_offset + ticks_s, tm); + timeutils_seconds_since_2000_to_struct_time(rtc_offset[1] + ticks_s, tm); } void common_hal_rtc_set_time(timeutils_struct_time_t *tm) { @@ -46,7 +63,13 @@ void common_hal_rtc_set_time(timeutils_struct_time_t *tm) { uint32_t epoch_s = timeutils_seconds_since_2000( tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec ); - rtc_offset = epoch_s - ticks_s; + rtc_offset[1] = epoch_s - ticks_s; + + // Set the prefix and suffix in order to indicate the time is valid. This + // must be done after the offset is updated, in case there is a crash or + // power failure. + rtc_offset[0] = RTC_OFFSET_CHECK_PREFIX; + rtc_offset[2] = RTC_OFFSET_CHECK_SUFFIX; } int common_hal_rtc_get_calibration(void) { diff --git a/ports/nrf/common-hal/rtc/RTC.h b/ports/nrf/common-hal/rtc/RTC.h index 0207c8338..e51f1f784 100644 --- a/ports/nrf/common-hal/rtc/RTC.h +++ b/ports/nrf/common-hal/rtc/RTC.h @@ -29,5 +29,6 @@ extern void rtc_init(void); extern void rtc_reset(void); +extern void common_hal_rtc_init(void); #endif // MICROPY_INCLUDED_NRF_COMMON_HAL_RTC_RTC_H |