I am testing the RTC code on the Muon (M404), and I am not able to get the device to wake up using a countdown or alarm. I have reproduced this in my own code and using the example code provided in AB1805_RK (specifically 04-selftest.cpp).
I have yet to dig through the schematics to confirm pin D28 (WDT) pin is the correct mapping. But I will do so in the meantime.
Additionally, I would like to test this using the M.2 breakout board using the Adalogger featherwing (RTC + SD). Will this library bridge an external RTC (PCF8523 is used) or do I need to integrate myself. I am working on firmware which functions with both the Muon and M.2 breakout for the m404 due to supply issues.
Is there a reason you need to wake from the AB1805? On Gen 4 devices (including the Muon and M-SoM) wake from duration works in all sleep modes. This is the preferred way to wake up a device.
The AB1805 was useful on Gen 3 devices (nRF52) because the RTC does not run in hibernate mode and there is no way to wake by duration when using hibernate (thought you can from ULP and STOP).
The Muon AB1805 FOUT/IRQ line is connected to RTC_INT. This is connected to the IO expander, not the MCU, and can't be used as a wake source at this time.
Ok understood. I went down this path because I was having issues with wake duration and assumed I was using it incorrectly. Now that I know that it's the preferred path I will do some more isolated testing.