XIAO BLE Sense in deep sleep mode

ekuleshov · March 2, 2023, 1:41pm

Yes, I looked at it. I also ended up not needed to wake up the board on a timer and using a pin interrupt instead which seems to work.

But the following note makes it not suitable for my needs, as I need to talk to BLE and Serial is needed for debugging. I was hoping it would have a “deferred” mode similar to regular Arduino pin interrupts, but it doesn’t.

github.com

khoih-prog/NRF52_TimerInterrupt/blob/33f86e8f00c6c60ded66e24d2d5011e978eb47be/examples/TimerInterruptLEDDemo/TimerInterruptLEDDemo.ino#L82-L92

      
        
            // In NRF52, avoid doing something fancy in ISR, for example complex Serial.print with String() argument
            // The pure simple Serial.prints here are just for demonstration and testing. Must be eliminate in working environment
            // Or you can get this run-time error / crash
            void doingSomething1()
            {
              digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
            
            
#if (TIMER_INTERRUPT_DEBUG > 0)
              Serial.println("G");
            #endif
            }

For the time being I ended up with SoftwareTimer which seem to be part of the standard library for XIAO. It is also somewhat low level and also doesn’t have “deferred” option for callback. But it supports one-time timers and BLE and Serial seems to work in the callback.

github.com

adafruit/Adafruit_nRF52_Arduino/blob/00d0801c1461ff60d563426ceffe87b8e3e919bd/libraries/Bluefruit52Lib/examples/Hardware/software_timer/software_timer.ino#L30-L59

      
        
            void setup()
            {
              // Configure the timer with 1000 ms interval, with our callback
              blinkTimer.begin(1000, blink_timer_callback);
            
            
  // Start the timer
              blinkTimer.start();
            }
            
            
void loop()
            {
              // do nothing here
            }
            
            

            
/**
             * Software Timer callback is invoked via a built-in FreeRTOS thread with
             * minimal stack size. Therefore it should be as simple as possible. If
             * a periodically heavy task is needed, please use Scheduler.startLoop() to
             * create a dedicated task for it.

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