Add DORMANT_CLOCK_SOURCE_RTC option on RP2040 #3048

2026-06-30T08:03:50-05:00

will-v-pi commented

2026-06-30 08:03:50 -05:00

(Migrated from github.com)

This runs RTC from XOSC, which allows going dormant without an external timer, at the expense of higher power consumption (about double DORMANT_CLOCK_SOURCE_XOSC, but still 5x less than sleep)

I think this is the lowest power the RP2040 can run at without an external clock source for the RTC, so is a useful option to add

This runs RTC from XOSC, which allows going dormant without an external timer, at the expense of higher power consumption (about double `DORMANT_CLOCK_SOURCE_XOSC`, but still 5x less than sleep) I think this is the lowest power the RP2040 can run at without an external clock source for the RTC, so is a useful option to add

kilograham (Migrated from github.com) reviewed

2026-06-30 08:03:50 -05:00

lurch (Migrated from github.com) reviewed

2026-06-30 08:54:58 -05:00

src/rp2_common/pico_low_power/include/pico/low_power.h

Does the "except clk_rtc which will be run from the XOSC" here mean that the "but XOSC and ROSC will be stopped" wording a few lines above needs to be changed? 🤷 (I'm afraid I never got to grips with all this clock-source stuff)

Does the "except clk_rtc which will be run from the XOSC" here mean that the "but XOSC and ROSC will be stopped" wording a few lines above needs to be changed? :shrug: (I'm afraid I never got to grips with all this clock-source stuff)

will-v-pi (Migrated from github.com) reviewed

2026-06-30 08:57:59 -05:00

src/rp2_common/pico_low_power/include/pico/low_power.h

I think I won't change it up there, but can add more to this note:

 * they can be stopped, except clk_rtc which will be run from the XOSC so that it continues running for the timer.
 * In this case the XOSC will not be stopped.

I think I won't change it up there, but can add more to this note: ```suggestion * they can be stopped, except clk_rtc which will be run from the XOSC so that it continues running for the timer. * In this case the XOSC will not be stopped. ```

				`@ -243,6 +250,13 @@ int low_power_dormant_until_aon_timer(absolute_time_t until, dormant_clock_sourc`
				`*`

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