One of the pins I am trying to use to wake the BW16 from deep sleep is PA15 - which should be possible.
However I am finding that this pin (called ‘9’ in the Arduino world, and pin 4 on the BW16) is not working properly.
I’ve written a more extensive post under the Freetos Peripherals forum,
but the summary is as follows:
When set up as an input with the pull-up enabled, the pin voltage measures 1.6V rather than the expected 3.3v.
If I attempt to force an external pullup with 4.7k to the 3v3 rail, it rises to 2.2V and I can use it as a wake-up signal, but the current consumption rises to over 0.2mA which for my battery powered device is not acceptable.
This behaviour is the same whether using Arduino or the SDK.
The device datasheet implies that this pin has dual-use - it can be part of an external 32kHz oscillator, and I suspect it is this circuit element which is preventing the correct GPIO behaviour.
There must surely be a way of managing the pinmux to avoid this, but I can’t find it.
I have tried setting the pinmux to PINMUX_FUNCTION_GPIO (0), and to PINMUX_FUNCTION_WAKEUP (31), but that 1.6v just persists.
Can anyone help me work out how to get pure GPIO functionality from this pin?