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6 years, 11 months ago.
InterruptIn: are they really pulled-down?
Hello, I'm using mBed for a nRF51822. I have a hardware pin interrupt waking up the BLE module just for a second, and it seems to work. However, in order to wake the MCU, I have to touch the wake pin to ground or take it off ground. Touching the wake pin to Vdd (3.3 volts or around there) does not wake the MCU.
On this InterruptIn page, it saids the default for InterruptIn is to use internal pull-down. But if that's the case, then grounding the interrupt pin shouldn't work. It seems like the deafult is to pull-up the interrupt pin.
https://developer.mbed.org/handbook/InterruptIn
I also get really high (200uA) current draw when the interrupt pin is left grounded. I'm assuming this is because the internal pull-up resistor is weak. How do I make this work if I expect the pin to be closed/opened for extended times and not consume too much battery power?
I think that note is old, and only applies to the original mbed board (when there was only one). Whether the pins are pulled down or up is probably board dependent. Check the datasheet for the nRF51822.
posted by Jan Jongboom 09 Jun 2017