Example needs logging.h

[WheeSci]

I am looking forward to trying your code but the example says that it needs logging.h to compile. can you point me to that repo?
Thanks, Jack

[matthias-bs]

Hi Jack,

You can find it in this repo in the directory src/logging.h.
https://github.com/matthias-bs/arduino-pico-sleep/blob/main/src/logging.h

Best regards,
Matthias

[WheeSci]

Thanks, I found it, moved the folders around and got the example to compile and load on my pico. In com port, I can enter the date and time but then it goes into sleep and never seems to come out. I put some Serial.println stuff in and found that it doesnt respond to anything after
sleep_us(64);
I commented that out and it hangs at the next line
pico_sleep(sleep_interval);
Any suggestions?
Thanks, Jack

[matthias-bs]

Which hardware are you using?

[WheeSci]

Standard raspberry pi pico (purchased from Digikey).
does this require rebuild of libpico.a?
Jack

[matthias-bs]

On one hand, you didn't provide much detail on on your hardware. But on the other hand, there is not much external circuitry which could have any influence. I used an Adafruit Feather RP2040 for the example code.
I don't think libpico.a has to be rebuild.
Did you check if your power supply remains stable even if almost no load is applied?

Another reason for an (apparent) hang-up might be that the USB-serial-interface fails to initialize/reconnect after wake-up. You might try to connect an external USB serial interface or check if the sleep/wakeup procedure works by other means (e.g. signalling activity using an LED).

[WheeSci]

Good call about using the led. It does appear that the USB interface is failing to reconnect.
About the hardware, The pico has headers soldered on and is plugged into a breadboard. The power comes from the usb cable to my laptop. There is nothing else attached.
When I perform tests using the on-board led, it appears that the board does wake up but does not connect to USB and does not return to the main loop:
I defined the on-board led as an output pin and pulled it HIGH in the setup(). In the prepareSleep() method, I set the led LOW after the pico_sleep(sleep_interval); command. With this code, the board powers up with the led lit. I then I enter the date and time and the led turns off after 60 s.
I put a series of commands into the loop() method that should blink the led, but it never does.
Also, I cannot re-program the board immediately after a test. I get a "no drive to deploy" error. If I unplug the board and re-plug it into the laptop, I can then re-program. This works without pressing the "BOOT SEL" button.

[matthias-bs]

Maybe it would be easier if you could make a fork and share your modified code.

The problem with the USB is that the host (PC) will loose connection to the device (pico) while it is in sleep mode and that you have to re-plug it to make it work again (either for serial debugging or for reprogramming).

As is, loop() is not run at all, because prepareSleep() ends with rp2040.restart();, which is a soft reset. This means you have to insert your LED blinking somewhere else.

If you switch the LED on at the start of setup() and switch it off before calling prepareSleep(), it should indicate when the pico is active. This assumes that the pico sleep does not have any negative on the GPIO pin control, which I don't remember any more.

My solution is far from being perfect or complete. I wish there were a decent support for sleep mode control in the Arduino pico package by now...