Compiling error when using ISR(USART0_RX_vect)

Using Arduino Programming Questions
1

Hi all,

I'm trying to use hardware serial interrupt with ISR macro on a Arduino mega 2560. I have got the following error message during compile

core.a(HardwareSerial.cpp.o): In function __vector_25':* *C:\arduino-1.0\hardware\arduino\cores\arduino/HardwareSerial.cpp:102: multiple definition of __vector_25'
HardSerial.cpp.o:C:\Users\MONPC~1\AppData\Local\Temp\build7790499637850564338.tmp/HardSerial.cpp:5: first defined here

ISR(USART_RX_vect)
{
  Serial.print("-");
}


void setup() {
  Serial.begin(9600);
  Serial.println("Init OK");
}

void loop(){
}

I don't understand this message and don't know what to do with.
Both Arduino V1.0 and V1.0.1 do the same. If i replace USART0_RX_vect by ADC_vect compilation is OK.

Thank you

2

You forgot the zero. You wrote ISR(USART_RX_vect). It should be ISR(USART0_RX_vect).

3

Thank you for your quick answer but, yes i forgot the 0 but even with it doesn"t wok.
I have also the same message with USART1_RX_vect, USART2, USART3

Thank you again
Fred

4

Are you getting compiler errors, or is the ISR not tripping? I don't know anything about these kinds of interrupts; I started a topic asking about them. I tried USART1_RX_vect, USART2_RX_vect, ... USART909_RX_vect, and got no compiler errors.

5

For the moment just :~ compiler error. After maybe problem with execution but it will be another story

6

I'm not sure that Serial.print(), etc. works inside ISRs. How come I'm not getting compiler errors? What are you trying to do? I don't know what the numbers after "USART" are for.
This, surprisingly, doesn't generate compiler errors [in Arduino 1.0.1], either (though it might not execute properly [or do anything at all]):

ISR(USART9098768797867_RX_vect)
{
  Serial.print("-");
}


void setup() {
  Serial.begin(9600);
  Serial.println("Init OK");
}

void loop(){
}
7

I don't know if this sketch works or not , for the moment i would like to compile it without error.
The number after USART0,1,2,3 is for serial com1,2,3,4. On the MEGA2560 you have 4 serial com interfaces.
I have no compile error if I write ISR(fred the wizard) but i have the following message if I write ISR(USART0_RX_vect)

core.a(HardwareSerial.cpp.o): In function __vector_25':* *C:\arduino-1.0\hardware\arduino\cores\arduino/HardwareSerial.cpp:102: multiple definition of __vector_25'
HardSerial.cpp.o:C:\Users\MONPC~1\AppData\Local\Temp\build7790499637850564338.tmp/HardSerial.cpp:8: first defined here

For me it's mean that USART0_RX_vect is define twice but where and how can I change that.

8

For me it's mean that USART0_RX_vect is define twice but where and how can I change that.

Stop trying to define your own interrupt with the same name. It's pretty simple, really.

Why are you trying to do that?

9

kwakiutls:
I'm trying to use hardware serial interrupt with ISR macro on a Arduino mega 2560.

Short answer. It already has one. As the error message indicates.

10

I'm also interested on this topic since I want to use interrupts on Serial port.In my case I want to have an interrrupt when serial data is on the buffer.On atmega 328 I found this register UCSR0B and there is a bit responsible for looking for that

bit 7 RXCIE0 RX Complete Interrupt Enable. Set to allow receive complete interrupts.

How can I do the interrupt to look to this register?
I'm trying to study the interrupts looking for the data sheet but is a real pain.Is there any good tutorial about general interrupts

11

since I want to use interrupts on Serial port.

Why?
There are interrupts, but they're already use, by the Serial object.

In my case I want to have an interrrupt when serial data is on the buffe

What's wrong with "Serial.available"?
Or serialEvent?

12

It is just because on the loop I don't want to get stuck trying to see if there is data on Serial buffer, I want to do another things and if I received something the CPU gets attention on that and process a interrupt function.I know it would be fine using serial.available but doing this way I hope get the code more efficient.
Did you agree?

13

It is just because on the loop I don't want to get stuck trying to see if there is data on Serial buffer, I

How can you "get stuck"?
There either is data, in which case you read it, or there isn't, in which case you carry on until there is.

Did you agree?

No, I don't.

14

Hello Nick

Short answer. It already has one. As the error message indicates

Does it mean that if I use Serial.xxx in my code, I cannot use ISR(USART0_RX_vect) because every definition are already done and link by using such declaration?

15

In its current form, yes. The serial port already has an interrupt handler, designed to grab incoming text and stuff it into a buffer.

This is what most people would write an interrupt handler to do.

Now you can edit the library and replace that code if you want to, but why do you want to? Are you planning to do something else, other than receive the incoming data, and put it into a buffer, and then set a flag to indicate it is there?

16

HugoPT:
I want to do another things and if I received something the CPU gets attention on that and process a interrupt function.I know it would be fine using serial.available but doing this way I hope get the code more efficient.

In what way would it get more efficient?

17

Isn't serialEvent() an ISR that triggers when serial data arrives? For the Mega, I think that it is serialEvent1(), serialEvent2(), and serialEvent3().

18

Isn't serialEvent() an ISR that triggers when serial data arrives? F

No, it is simply called after each iteration of "loop"

19

Thanks to all of our discussion, particularly to Nick Gammon, I just write my own code to trip a serial interrupt in the event of receiving a char.
I know now that the Serial object already use interrupt, it's why when I use ISR(USART0_RX_vect) and Serial.open() I got an compile error which explain that _vector_25 already defined.

I use MEGA2560 wich as 4 USART. For other microcontroller internal name register may differ, also divider for baud generation wich depend on osc frequency. Atmel datasheet are well explain and very complete.

volatile int incom = 0;

//INTERRUPT WHEN A BYTE COMING
ISR(USART0_RX_vect){
incom=UDR0; //RECEIVE THE BYTE ON RX
UDR0=incom; //SEND IT IN ECHO ON TX
}

void setup() {
pinMode(13,OUTPUT);

cli(); //DISABLE ALL INTERRUPTIONS

//REGISTRE UBRR0
//9600 BAUD FOSC=16MHZ
UBRR0=103;

//REGISTRE USCR0C
//COM ASYNCHRONE
bitWrite(UCSR0C,UMSEL00,0);
bitWrite(UCSR0C,UMSEL01,0);

//PARITY NONE
bitWrite(UCSR0C,UPM01,0);
bitWrite(UCSR0C,UPM00,0);

//8 DATA BIT
bitWrite(UCSR0C,UCSZ02,0);
bitWrite(UCSR0C,UCSZ01,1);
bitWrite(UCSR0C,UCSZ00,1);

//REGISTRE UCSR0B
//RECEIVE & TRANSMITT ENABLE
bitWrite(UCSR0B,RXEN0,1);
bitWrite(UCSR0B,TXEN0,1);

//ENABLE RX COMPLETE INTERRUPT
bitWrite(UCSR0B, RXCIE0,1);

sei(); //ENABLE INTERRUPTION
}

void loop(){ // IN THIS LOOP NOTHING IMPORTANT ONLY TOGGLE ON/OFF PIN13
digitalWrite(13,1);
delay(500);
digitalWrite(13,0);
delay(500);
}

Thanks again