Deepest sleep mode to wake up from without user input

Discussion about wireless devices

Deepest sleep mode to wake up from without user input

Postby justind000 » Fri Feb 20, 2015 5:38 pm

I have been experimenting with putting the le1 to sleep. My goal is to put it in a deep a sleep as possible and have it wake up on its own at a specified interval. I have tried setting the maximum time for the watchdog and letting it reset, but this does not appear to work in any mode other than active. I have only been able to get it to sleep in pwr_clk_mgmt_enter_pwr_mode_memory_ret_tmr_on mode and waking up on rtc2 TICK, but I can only seem to get a tick interval of 2 seconds max. I can also wake up from standby from an RFIRQ, but standby uses more current than I'd like for my battery powered device.

Am I missing any other options or using what I described incorrectly? A full reset would be fine for my purposes if it coincided with a relatively long sleep time.
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Re: Deepest sleep mode to wake up from without user input

Postby brennen » Fri Feb 20, 2015 6:36 pm

Using RTC2 and TICK are the only way I've found to wake the device from sleep on an interval, and I also agree that the 2 second limitation is wayyy too short. The only other option I know of is to use a super low current external RTC and use wakeup on pin interrupt for the LE1. I'm not sure if that would get you with a lower power consumption or not. It would definitely be a higher cost in parts, though.
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Re: Deepest sleep mode to wake up from without user input

Postby justind000 » Mon May 18, 2015 2:09 am

Figured it out and made it into a small macro

Code: Select all
#define watchdogRun(p1) watchdog_start_and_set_timeout_in_ms(p1);CLKLFCTRL=1

watchdogRun(1000);


That will let you go down to PWR_CLK_MGMT_PWRDWN_MODE_MEMORY_RET_TMR_OFF and then reset after 1000 milliseconds. Doesn't work in deep sleep. The trick was to turn on the other timer. I guess reading the datasheet pays off every now and then.
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