Seeed XIAO BLE Sense pinMode() and digitalWrite() stop working after Wire.end()

Products & Technology Arduino & Seeeduino
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#1

I was using Arduino Wire library to perform I2C master. The board I selected was Seeed nRF52 mbed-enabled boards → Seeed XIAO BLE Sense - nRF52840. The SCL was a multi-purpose pin which sometimes needed to be controlled with pinMode() and digitalWrite() after I2C communications. The problem I encountered was, once the I2C communication already happened, if I wanted to take SCL back with Wire.end(), pinMode() and digitalWrite() had no effect. Here is the code,

      Wire.end();

      digitalWrite(SCL_PIN, HIGH);
      pinMode(SCL_PIN, OUTPUT);
      digitalWrite(SCL_PIN, LOW);
      delayMicroseconds(5000);
      digitalWrite(SCL_PIN, HIGH);
      pinMode(SCL_PIN, INPUT);

      Wire.begin();
      Wire.setClock(400000UL);

I tried multiple SCL pins. None was working.
Any help will be highly appreciated.

#2

Hi there,
You may want to Use the GPIO pin number directly after the Wire.end.
See if that works. (perhaps the macro I2C doesn’t release it?)
my .02
HTH
GL :slight_smile: PJ

#3

It doesn’t seem possible. Actually, if I put the same pinMode() and digitalWrite() before Wire.begin() was ever called, I could see the pulse I generated on SCL.

#4

Hi there,
That seems normal , If before it’s called. What about a hard coded end of transmission? or transaction possible? Why wouldn’t it release it’s config of the pin?
Can you put some delay in there, Like a whole second or even try “Delay(500);” a half sec.
LMK,
GL :slight_smile: PJ
can you post the code here? and why 2 threads?

#5

i think wire end is designed to end the wire configuration, and would be expected to clean up nd free those pins…