Cold sleep wakeup by pin on extension board not possible?
I am using the ExternalWakeup example.
It seems that digital GPIO pins on the LTE Extension board do not work as wake up pins.
The pins seem to work well triggering interrupts while the Spresense board is on. However these pins either always trigger wakeup immediately or never trigger a wakeup depending on the setup of pull-up/pull-down, RISING/FALLING and how you connect the pins.
Having no success trying out a lot of combinations (Actually I used an accelerometer that has a configurable interrupt pin triggered by movement before switching to ExternalWakeup), I tried the ExternalWakeup using pins on the main board. This works perfectly well.
- Can you confirm that pins on the LTE extension board cannot be used as wakeup pins for cold sleep?
- I have a 3.3V accelerometer. How could I connect the interrupt pin to the main board GPIO?
It seems to work when I use my own level shifter and connect to digital pin 01.
I used this https://www.adafruit.com/product/1875.
However when I tried to use the 3.3V pin on the LTE board, I noticed that it reads 0.0V on my multimeter. (Main power is available on the LTE board though)
The accelerometer mentioned is connected via breakout on the mainboard by this https://www.switch-science.com/products/6318?_pos=5&_sid=a0079aea0&_ss=r. So it was not affected by the "power down" (?) on the LTE board.
- Could you still please clarify above questions.
- And add this to the documentation (I did not find any hint.)
Also the ExternalWakeup sample does not really work or does the non-LTE extension board behave differently? It would make sense to use the button pin 33 in the sample. That seems to work as it is connected to 1.8V directly.
Sorry for the delayed response.
I was just trying out the sketch here and everything worked well in all three boards (main, extension and LTE)
Using the LTE extension board I changed button 2 to PIN_D29.
To trigger the interrupt I connected it to GND, since we are using INPUT_PULLUP configuration.
So to answer the first question, the pins on the LTE extension board can be used as wakeup pins for cold sleep.
For the second question I think you already fixed it by using your own level shifter, right?
Let me know if you are still struggling with this topic and if I can provide any further help.