And… here we are

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This week what we have all been fearing has happened to me: GitHub Copilot generated code for me which seems to meet all the requirements but which I don’t understand very much at all.

To date GitHub Copilot for me has just been mostly a useful auto-complete tool and it hasn’t given me any code which I didn’t understand. But with this code (to control two different hardware timers/counters on my Arduino) I don’t really understand it at all. I have passing familiarity with some of the registers used because I saw them named in the datasheet (which I have only skimmed so far) but basically I don’t understand how this works.

It is tempting to ignore the fact that I don’t fully understand and move on, but there’s a part of me which wants to return to the datasheet so I can understand what every assignment GitHub Copilot offered actually does and what every value it calculated implies. Is that the best use of my time?

Controlling Arduino Uno with Serial commands

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@kline helped me with Phase 1 of my Crustacean Chirpy Chip Challenge project, which I have completed (sort of). I got the programming done but I didn’t do all the reading (yet).

Note to self: My Arduino Uno knockoff identifies itself as a “QinHeng Electronics USB Serial” USB device.

This is my code:

enum state { OFF, ON, FLASH };

enum state state = OFF;

int blink_pin = 13;

void setup() {
  pinMode( blink_pin, OUTPUT );
  Serial.begin( 9600 );
}

void loop() {
  if ( Serial.available() > 0 ) { read_command(); }
  switch ( state ) {
    case ON :
      digitalWrite( blink_pin, HIGH );
      break;
    case OFF :
      digitalWrite( blink_pin, LOW );
      break;
    case FLASH :
      int pin = digitalRead( blink_pin );
      digitalWrite( blink_pin, !pin );
      delay( 500 );
      digitalWrite( blink_pin, pin );
      delay( 500 );
      break;
  }
}

void read_command() {
  String command = Serial.readString();
  command.trim();
  command.toLowerCase();
  Serial.print( "Command: " );
  Serial.println( command );
  if ( command == "on" ) {
    state = ON;
  }
  else if ( command == "off" ) {
    state = OFF;
  }
  else if ( command == "flash" ) {
    state = FLASH;
  }
  else {
    Serial.println( "Unknown command." );
  }
}

This is my setup:

The code which would actually implement the spec, as given:

void read_command() {
  char c = Serial.read();
  switch ( c ) {
    case 'a' :
      state = ON;
      break;
    case 's' :
      state = OFF;
      break;
  }
}

Embedded Systems with ARM Cortex-M Microcontrollers in Assembly Language and C

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Today I learned about Embedded Systems with ARM Cortex-M Microcontrollers in Assembly Language and C (Fourth Edition) by Yifeng Zhu while watching Lecture 9: Interrupts on YouTube. The full list of associated lectures are here: Short Lectures.