I2C Master Read Slave Pin

Using Arduino Networking, Protocols, and Devices
#1

Maybe a simple question, but I am not having any luck researching by myself...

I want an Arduino Master to get the digital on or off condition of a pin, lets say 13 for this example.

I have succeeded in getting the 2 to communicate on I2c, but I cannot find how to monitor the high or low state of each pin on the slave.

Thanks

#2

You could found one way to do it from here and get some ideas to write your requestCallback()-function with digitalRead.. Especially this part might interest you:

//For slave

#include
 
const byte AnalogueInputPin = 0;
const byte SlaveDeviceId = 1;
 
void setup()
{
  // Start I²C bus as a slave
  Wire.begin(SlaveDeviceId);
  // Set the callback to call when data is requested.
  Wire.onRequest(requestCallback);
}
 
void loop()
{

}
 
void requestCallback()
{
  // Contrived example - transmit a value from an analogue pin.
  int input = analogRead(AnalogueInputPin);
 
  // To send multiple bytes from the slave,
  // you have to fill your own buffer and send it all at once.
  uint8_t buffer[2];
  buffer[0] = input >> 8;
  buffer[1] = input & 0xff;
  Wire.write(buffer, 2);
}

Master just have to keep sendind requests to the slave..

TommiP

#3

Pirate_Duino:
Maybe a simple question, but I am not having any luck researching by myself...

I want an Arduino Master to get the digital on or off condition of a pin, lets say 13 for this example.

I have succeeded in getting the 2 to communicate on I2c, but I cannot find how to monitor the high or low state of each pin on the slave.

Thanks

in the Slaves onRequestEvent(),

void onRequestEvent(){

uint8_t pins[3];

pins[0] = PIND; //  digital 0..7  Pin0,1 are RX,TX

pins[1] = PINB; // port B pins, 8,9,10,11,12,13 ,
pins[1] = pins[1] & B00111111;  // the two high bits are actually connected to the crystal

pins[2] = PINC;//  Analog Pins 0..5
pins[2] = pins[2] & B00111111; // Bit 7,6 are not visible on the 328p, also A5, A4 are the I2C pins

Wire.write(&pins,3);
}

You will have to have the Master issue a Wire.requestFrom(slaveid,3);

And you will receive three bytes with all of the Slave Arduino Pin States.

Chuck.

#4