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adafruit / Adafruit_nRF52_Arduino

Adafruit code for the Nordic nRF52 BLE SoC on Arduino
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Pin names don't match pin diagram in documentation #733

Closed zfields closed 2 years ago

zfields commented 2 years ago

Operating System

Linux

IDE version

Arduino CLI 0.22.0

Board

Feather nRF52840 Express

BSP version

adafruit:nrf52@1.3.0

Sketch

//#define BUTTON 2 // 2 comes from the pinout diagram (attached)
#define BUTTON 0 // 0 should belong to TX based on the pinout diagram

volatile bool isr_fired = false;

void buttonISR () {
    isr_fired = true;
}

void setup () {
    ::pinMode(LED_BUILTIN, OUTPUT);
    ::pinMode(BUTTON, INPUT);
    ::attachInterrupt(digitalPinToInterrupt(BUTTON), buttonISR, RISING);
}

void loop () {
    if (isr_fired) {
        isr_fired = false;
        ::digitalWrite(LED_BUILTIN, HIGH);
        ::delay(250);
    }
    ::digitalWrite(LED_BUILTIN, LOW);
}

What happened ?

With a momentary button connected to D2, when I define BUTTON as 2 the LED does not flash. With a momentary button connected to D2, when I define BUTTON as 0 the LED flashes.

The RX pin can be used by defining BUTTON as 1 as expected. The TX pin does not respond to defining BUTTON as 2.

How to reproduce ?

  1. Wire up a momentary button and try using it with the pin labeled D2.

Debug Log

No response

Screenshots

This pinout diagramis clearly for the nRF52840 Feather Sense, but it is the only pinout diagram offered from the nRF52840 Feather Express Guide

image

ajs123 commented 2 years ago

D2 is not available as an input (it’s configured for the NFC antenna) unless you do a one-time (and hard to reverse) reconfiguration. See issue 728.

Of course, that doesn’t explain what you’re seeing when specifying pin 0. When I encountered the issue described in 728, D0 (TX) was one of my test pins and it worked as it should.

zfields commented 2 years ago

Were you using the Adafruit Feather nRF52840 Express or the Adafruit Feather nRF52840 Sense board?

hathach commented 2 years ago

@zfields as mentioned by @ajs123 D2 on Feather express and sense are the same (NFC GPIO P0.10). You will need to one-time run nfc2gpio sketch to convert it from NFC to gpio https://github.com/adafruit/Adafruit_nRF52_Arduino/blob/master/libraries/Bluefruit52Lib/examples/Hardware/nfc_to_gpio/nfc_to_gpio.ino

check out #728 for detail

zfields commented 2 years ago

@hathach, I have a couple of questions...

  1. Where did @ajs123 mention "Feather express and sense are the same"?
  2. I did not run that sketch on my Feather nRF52840 Express and, as the issue states, it works as GPIO on pin 0. :shrug:
hathach commented 2 years ago
  1. the issue is D2 is NFC P0.10 (same on feather express), which may need to be converted to from NFC function to GPIO
  2. D0 is not NFC-capable as D2

If you would like D2 to be used as GPIO like D0, please read the other issue for explanation and run the sketch.

closed since duplicated to #728

zfields commented 2 years ago

@hathach There is a miscommunication...

D2 (the physical pin) responds programmatically to 0.

As in, 

pinMode(0,INPUT);
int d2_pin_value = digitalRead(0);

I have not run any scripts on my Feather nRF52840 Express, it is EXACTLY as it came from the Adafruit store.

hathach commented 2 years ago

Sorry if I mis-understood your description and/or didn't say it clear enough. D2 cannot be (reliably) used as GPIO without running the nfc_to_gpio sketch first. Why it responses as if it is pin0 is an accident/mystery/bug I can't explain.

I have not run any scripts on my Feather nRF52840 Express, it is EXACTLY as it came from the Adafruit store.

yeah, and you need to run it once if you are using stock board + bootloader for D2 to work as gpio. We did auto-convert it to gpio in later bootloader version, if you don't want to run the sketch, just burn the latest bootloader

Sum up: