Embedded Programming

Programming ATtiny 412 with Arduino IDE

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For the beginners like me, Arduino IDE would be the best choice to start programming. There are many examples with comprehensive explanations available. I started with using programs, made by the students last year.

With this knowledge I'm ready to proceed:

• Simply connect programmer with 3 pin female connector of the board
• I took the Arduino sketch example from Arash's page, to make LED blinking the number of times the BUTTON is pressed. I changed the pin's number for BUTTON and LED.
• Settings in Arduino IDE:
  
  

  Fig 3. Arduino IDE to upload the sketch on the board.

Unfortunatly, nothing have happened. Therefore, I decided to simplify the program, just to check if my LED works. I used the simplest available Arduino sketch:

void setup() {
// put your setup code here, to run once:
pinMode(3, OUTPUT);
}

void loop() {
// put your main code here, to run repeatedly:
digitalWrite(3, HIGH);
delay(100);
digitalWrite(3, LOW);
delay(100);
}

Again, nothing happened, even though sketch uploading was successful. To ensure, that programming is happening, I tried the previous echo program with Putty, which worked. After I uploaded the new program, I checked Putty, and it stopped responding, meaning, that programming is happening succesfully. Eventually, HUGE THANKS to Gleb, and our intructor Ari, who sent us help just few minutes later, after I succeed with a programming.

The ISSUE is that the pinout of Attiny412 is different from the pinout in Arduino IDE megaTinyCore. This Gitlab page reports: "WARNING: On pre 2.0.0 versions of megaTinyCore, the UART defaulted to the alternate positions This matches the megaTinyCore 412/402 Rev. - and Rev. A breakout boards below. In 2.0.0 and later, this is no longer the case! You must call Serial.swap(1) prior to Serial.begin() to move it to the alt pins (or connect your adapter to pins 0 and 1 instead of 2 and 3)."

Fig 4. The correct Attiny412 pinout.

• VDD: Supply voltage.
• GND: Ground.
• Digital pins: PA0, PA1, PA2, PA3, PA4, PA5, PA6.
• Analog pins: PA1, PA2, PA3, PA4, PA5, PA6.
• UPDI Programming: PA0 (physical pin number 6).
• External Clock: PA3.

Therefore, the pins in the sketch should be defined as:

Output LED pin number is 1
and the Input BUTTON pin is 0.

I'm trying the LED pin set to 1, and it works now!

Another example, when the button is pressed, the light is turned off:

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// constants won't change. They're used here to set pin numbers:
const int buttonPin = 0; // the number of the pushbutton pin
const int ledPin = 1; // the number of the LED pin

// variables will change:
int buttonState = 0; // variable for reading the pushbutton status
int lastButtonState = 0;

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);
// check if the pushbutton is pressed. If it is, the buttonState is HIGH:
if (buttonState != lastButtonState) {
if (buttonState == HIGH){
digitalWrite(ledPin, HIGH);
}
else {
digitalWrite(ledPin, LOW);
}

}
lastButtonState = buttonState;
}
  
  

One more code, which joins the serial monitor with LED function: typing 1 in a serial monitor the LED will light up, and typing 0 with turn it off.

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int outPin = 1;
void setup(){

pinMode(outPin,OUTPUT);
Serial.begin(112500);
Serial.println("Enter 1 or 0");
}
void loop(){
if(Serial.available()>0)
{
char ch = Serial.read();
if (ch == '1')
{
digitalWrite(outPin,1);
}
else if (ch == '0')
{
digitalWrite(outPin,LOW);
}
}
}

Fig 5. Sending 1 through the Serial lighten up the LED.

Arduino sketches:

• LED blink
• LED off by BUTTON
• Serial control the LED