arduino i2c slave

[carbon dude oxide]

hello, i am having trouble finding some form of code example which turns my arduino into an i2c slave which just receives 2 bytes of data at a time.

i currently have this:

Code: [Select]

#include <Wire.h>

#define A 7
#define B 6
#define C 9
#define D 12
#define E 13
#define f 10
#define G 11
#define P 8
#define D1 5
#define D2 4
#define D3 3
#define D4 2

String displays[] = {"x", "x", "ABCDEF", "ABCDEF", "ABCDEFP", "X"};

void setup() {
  // put your setup code here, to run once:
  pinMode(D1, OUTPUT);
  pinMode(D2, OUTPUT);
  pinMode(D3, OUTPUT);
  pinMode(D4, OUTPUT);
 
  pinMode(A, OUTPUT);
  pinMode(B, OUTPUT);
  pinMode(C, OUTPUT);
  pinMode(D, OUTPUT);
  pinMode(E, OUTPUT);
  pinMode(f, OUTPUT);
  pinMode(G, OUTPUT);
  pinMode(P, OUTPUT);
  Serial.begin(9600);
  Wire.begin(2);                // join i2c bus with address #2
  Wire.onReceive(requestEvent) // register event
 
}

void loop() {
  // put your main code here, to run repeatedly:
  //Serial.println(',', DEC);
  for (int i=5; i>1; i--) {
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
    digitalWrite(5, LOW);
   
    digitalWrite(A, LOW);
    digitalWrite(B, LOW);
    digitalWrite(C, LOW);
    digitalWrite(D, LOW);
    digitalWrite(E, LOW);
    digitalWrite(f, LOW);
    digitalWrite(G, LOW);
    digitalWrite(P, LOW);
   
    if (displays[i].indexOf('A') > -1) {digitalWrite(A, HIGH);}
    if (displays[i].indexOf('B') > -1) {digitalWrite(B, HIGH);}
    if (displays[i].indexOf('C') > -1) {digitalWrite(C, HIGH);}
    if (displays[i].indexOf('D') > -1) {digitalWrite(D, HIGH);}
    if (displays[i].indexOf('E') > -1) {digitalWrite(E, HIGH);}
    if (displays[i].indexOf('F') > -1) {digitalWrite(f, HIGH);}
    if (displays[i].indexOf('G') > -1) {digitalWrite(G, HIGH);}
    if (displays[i].indexOf('P') > -1) {digitalWrite(P, HIGH);}
    digitalWrite(i, HIGH);
    delay(1);
  }
}
void requestEvent()
{
  Wire.receive("hello "); // respond with message of 6 bytes
                       // as expected by master
}
void test()
{
  byte icstart = B00000000;
  byte icend = B00000000;
  while (Wire.available() > 1){
    icstart = Wire.receive();
    icend = Wire.receive();
  }
  }
}
can someone help me with this please

[redben]

If you want a bit more help, you'll probably have to describe a bit more your project and your problem with it.
Apparently in this piece of code you don't even share data via I2C bus.
Are you trying to display things on LCD ? "if (displays.indexOf('A') > -1) {digitalWrite(A, HIGH);}"
What are the two devices you try to connect together ?
If it is a pc it is probably much simpler to establish a serial connection via usb.

[dannyf]

"an i2c slave which just receives 2 bytes of data at a time."

The easiest would be to use an interrupt.