TXCIE Interrupt on Arduino MEGA

Projects Programming
1

Hi,
I want to use the TXCIE Arduino MEGA interrupt. I wrote this pilot project. First the setup runs normally and LED_BUILTIN flashes once and then prints "11111000" intermittently, but the LED does not light up!
Please guide me if there is a mistake.


ISR(USART_TXC0_vect){
  digitalWrite(LED_BUILTIN, HIGH);
}

void setup() {
 Serial.begin(9600);
  Serial.println("Setup...");
  pinMode(13,OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);   
  delay(1000);                      
  digitalWrite(LED_BUILTIN, LOW);    
  delay(1000);      
}
void loop() {

 Serial.println(UCSR0B,BIN);
  UCSR0B |= (1<<TXCIE0);
  sei();
}
2

What’s your purpose for this project ?

3

Should that be "USART_TX_vect" ?

4

With thanks for your attention, I want to use this interrupt to control the RS485 direction. As far as I saw we can use udre to drive rs485, which is not a good method because Ardino uses this interrupt, and on the other hand, this interrupt specifies the end of each character, not the end of the message. Delay is usually suggested which it is not desirable for my project.

5

https://www.nongnu.org/avr-libc/user-manual/group__avr__interrupts.html

6

thanks for your answer
Mega 2560 has four serial ports. Of course, your point was also correct that I wrote it incorrectly and it should be written as follows

ISR(USART0_TX_vect)
7

Thanks a lot
The code was modified as follows and works properly.

uint8_t state=0;

ISR(USART0_TX_vect){
  state=1;
}

void blink_LED(){
  digitalWrite(LED_BUILTIN, HIGH);  
  delay(1000);                      
  digitalWrite(LED_BUILTIN, LOW);    
  delay(1000);  
}

void setup() {
 Serial.begin(9600);
  Serial.println("Setup...");
  pinMode(LED_BUILTIN,OUTPUT);
  blink_LED();
  UCSR0B |= (1<<TXCIE0);
  sei();
}
void loop() {
  
Serial.println(UCSR0B,BIN);
if (state){
  state=0;
  blink_LED();
}
}