ESP8266 Community Forum

- Tue Aug 04, 2015 10:55 am #25009 For the esp8266 RTC probably means Real Time Counter since that is all that it does...it doesn't mean Real Time Clock. Now with a known elapsed time between a tick of the real time counter the ticks could be converted to elapsed seconds minutes hours etc. An external reference such as an internet time server would allow a transform to a real time clock.

- Tue Aug 04, 2015 11:00 am #25010 You're right ! (My bad, I've relook at the specs)

"DEEP_SLEEP: Only RTC is powered on" (But, unfortunately, Espressif doesn't provide much details, even the RTC is now shown in the block diagram, so, that's why it confused me)

- Tue Aug 04, 2015 2:43 pm #25027 hmm, the rtc is always running, that is what wakes the device from sleep, since that is settable counter (you can use different times) then it already has some fairly functional hardware that operates while the cpi is snoozing. So it cannot just be emulated in software.
Then page 18 of the programming guide says ..

3.2.13. system_get_rtc_time
Function：Get RTC time , count by RTC clock period.
Example: If system_get_rtc_time returns 10 (means 10 RTC cycles),
system_rtc_clock_cali_proc returns 5 (means 5us per RTC cycle), then real
time is 10 x 5 = 50 us.
Note: System time will return to zero because of deep sleep or system_restart,
but RTC still goes on.
Prototype：
uint32 system_get_rtc_time(void)
Parameter：
Null
Return：
RTC time.

- Thu Aug 06, 2015 8:35 am #25185 found in release_note.txt for the current falcon SDK

Document "2C_ESP8266__Programming Guide" updates:
1.Update Demo code of rtc timer in appendix, and rtc timer will return to zero after deep-sleep wake up. [andrew]