Dear forum,
I'm working on the I2C connection between UNO R4 and the Modulino Button module. The button status I want to catch by an interrupt routine.
Please refer to the code I attach.
void setup() {
Wire1.begin(); // join i2c bus (address optional for master)
Serial.begin(9600); // start serial for output
Wire1.onReceive(receiveEvent);
Serial.println();
Serial.println("Start");
}
void loop() {
Wire1.requestFrom(62, 6); // request amount bytes from peripheral device #62
delay(500);
}
void receiveEvent(int howMany) {
while (howMany-- > 0) {
uint8_t c = Wire1.read();
Serial.print(c, HEX);
Serial.print(" ");
}
Serial.println();
} // end of receiveEvent
What I'm doing is: The requestFrom() is in the loop() placed, but the answer from the I2C device shall be catched by the interrupt routine. This does not work for what reason?
I seems that the ISR routine is well attached but not called.
Does anyone now the reason?
Thanks for any hint by
CTrenet
"In this case the I2C library is designed to handle incoming I2C bytes internally, and then call your supplied function at the end of the incoming data stream. In this case receiveEvent is not strictly an ISR (it has an argument) but it is called by an inbuilt ISR."
Yes, I did. I could not see a code line calling the receiveEvent handler in the Moduline lib.
I'm working with the Wire.h lib. I can see there the transfer of pointer by receveEvent and the call to the ISR (receiveEvent), but obviously it's not supported without further code.
from Wire.cpp
// behind the scenes function that is called when data is received
void TwoWire::onReceiveService(uint8_t* inBytes, int numBytes)
{
// don't bother if user hasn't registered a callback
if(!user_onReceive){
return;
}
// don't bother if rx buffer is in use by a master requestFrom() op
// i know this drops data, but it allows for slight stupidity
// meaning, they may not have read all the master requestFrom() data yet
if(rxBufferIndex < rxBufferLength){
return;
}
// copy twi rx buffer into local read buffer
// this enables new reads to happen in parallel
for(uint8_t i = 0; i < numBytes; ++i){
rxBuffer[i] = inBytes[i];
}
// set rx iterator vars
rxBufferIndex = 0;
rxBufferLength = numBytes;
// alert user program
user_onReceive(numBytes);
}
