ESP8266 Developer Zone

Re: Why is RTC timer lost during deep sleep?

2017-10-19T20:30:24+08:00

There is a mistake in the documentation about this subject.

In the datasheet, section 3.6:

"ESP8266EX consumes about 20 μA of power in Deep-sleep mode (with RTC clock still running)".

This is wrong, the clock is running, but the register of the RTC timer counts from zero.
I came with this conclusion, by testing and reading the RTOS SDK programming guide, section 3.2.10:

"When software restart (system_restart) is executed, the system time will return to zero,
while the RTC timer will continue. However, if the chip is woken up (including being
periodically woken up from Deep-sleep mode) via external hardware (including EXT_RST
pin or CHIP_EN pin), the RTC timer will be restarted.
• external reset (EXT_RST): the RTC memory does not change; the register of the RTC
timer counts from zero."

Statistics: Posted by mpamplona — Thu Oct 19, 2017 8:30 pm

Re: Why is RTC timer lost during deep sleep?

2015-12-14T16:56:08+08:00

Will RTC timer keep running in deep sleep when connecting PIN VDD_RTC?

Statistics: Posted by SpenZerX — Mon Dec 14, 2015 4:56 pm

Re: Why is RTC timer lost during deep sleep?

2015-12-05T19:32:05+08:00

Add external RTC, their very cheap (using I2C for example).

Statistics: Posted by eriksl — Sat Dec 05, 2015 7:32 pm

Re: Why is RTC timer lost during deep sleep?

2015-12-03T01:31:36+08:00

Reset RTC to 0 is real problem for me, I use deep-sleep, and during sleep time interrupt from external sensor may occur. External sensor connected to RESET line of ESP8266 and must wake up module, but after wake-up I can't calculate time was sleeping (and time left). Can you give some mechanism for direct RTC control? I didn't found detailed description of RTC module (registers, control bits and so on).

Statistics: Posted by Dmytro — Thu Dec 03, 2015 1:31 am

Re: Why is RTC timer lost during deep sleep?

2015-10-15T15:50:43+08:00

Interesting though, because the RTC is supposed to keep running in deep sleep, because it needs to be able to wakeup the rest of the chip...

Statistics: Posted by eriksl — Thu Oct 15, 2015 3:50 pm

Re: Why is RTC timer lost during deep sleep?

2015-10-13T09:47:13+08:00

Hi,

Sorry for the inconvenience.

ESP8266 designed like this, wake up from deep-sleep, the RTC timer will be reset, but the data stored in RTC memory will not.

You could call system_get_rtc_time before deep-sleep and write the value into RTC memory by system_rtc_mem_write.

Statistics: Posted by ESP_Faye — Tue Oct 13, 2015 9:47 am

Re: Why is RTC timer lost during deep sleep?

2015-10-08T14:35:20+08:00

I'm interested in this question too -

When the chip awaken, the RTC clock (system_get_rtc_time) is reset to 0

It would be really useful if there was a way to prevent that happening.

Statistics: Posted by torntrousers — Thu Oct 08, 2015 2:35 pm

Re: Why is RTC timer lost during deep sleep?

2015-10-04T02:12:46+08:00

Thanks for the note about the reset reason, it is fixed in 1.4!

The fact that the RTC clock is reset is still a puzzle.

Statistics: Posted by tve — Sun Oct 04, 2015 2:12 am

Re: Why is RTC timer lost during deep sleep?

2015-10-03T23:16:23+08:00

tve wrote:
is it expected that after a deep sleep system_get_rst_info->reason == REASON_EXT_SYS_RST and not REASON_DEEP_SLEEP_AWAKE ?

That is a bug in v1.3.0 (and probably earlier) of the SDK. It was fixed in a special build of v1.3.0 but I haven't checked to see if the correction made it into v1.4.0.

Statistics: Posted by dkinzer — Sat Oct 03, 2015 11:16 pm

Re: Why is RTC timer lost during deep sleep?

2015-10-03T15:01:13+08:00

By the way, is it expected that after a deep sleep system_get_rst_info->reason == REASON_EXT_SYS_RST and not REASON_DEEP_SLEEP_AWAKE ?

Statistics: Posted by tve — Sat Oct 03, 2015 3:01 pm

Why is RTC timer lost during deep sleep?

2015-10-03T14:44:52+08:00

Is it a design feature that the RTC timer is lost during deep sleep? I observe the following (using SDK 1.3):

The chip is awakened from deep sleep after a timer expiration using a gpio16->ext_rst connection

The RTC memory (system_rtc_mem_read/write) is preserved during deep sleep

The RTC clock must be running during deep sleep since it awakens the chip

When the chip awaken, the RTC clock (system_get_rtc_time) is reset to 0Why?

Statistics: Posted by tve — Sat Oct 03, 2015 2:44 pm