Canzasi_I2Cblink.ino

// Canzasi_I2Cblink
// A simple I2C slave receiver
//   LED blinking of synchronous when slave received 
//   "write" data from master.
// with https://github.com/SpenceKonde/ATTinyCore
// 
// License CC by 4.0 2016 D.F.Mac.
//
//                   +----+
//                VCC|    |GND
// LED    PB0/A11/ D0|    |D10/A0 /PA0
// ERRLED PB1/A10/ D1|    |D9 /A1 /PA1
//        PB3/ A9/D11|    |D8 /A2 /PA2
//        PB2/ A8/ D2|    |D7 /A3 /PA3
//        PA7/ A7/ D3|    |D6 /A4 /PA4    SCL
// SDA    PA6/ A6/ D4|    |D5 /A5 /PA5
//                   +----+
//
#include "i2c841s2.h"

#define LED_PIN 0     // PB0
#define ERRLED_PIN 1  // PB1

uint8_t errorFlg = false;

void onI2CWrite(volatile uint8_t *pbuf, uint8_t size){
 
  // The i2cs's default rx buffer is used in this sample. 
  // buffer length is 1 byte.
  
  if(size == 1){   // Correct packet length
    if(*pbuf == 1){
      digitalWrite(LED_PIN,HIGH);
    }else{ 
      digitalWrite(LED_PIN,LOW);
    }
  }else{          // Incorrect packet length 
    errorFlg = true;
  }
}

void setup() {
  pinMode(LED_PIN,OUTPUT);
  pinMode(ERRLED_PIN,OUTPUT);
  
  i2cs.setOnWriteEnd(onI2CWrite);
  
  // default rx buffer length (per packet size) is 1 byte
  // if slave device specified another size, use i2cs.setRxBuffer()

  // start i2c slave interrupt
  i2cs.init(0x30);            
}

void loop() {  
  if(errorFlg){
    digitalWrite(ERRLED_PIN,HIGH);
    delay(100);
    digitalWrite(ERRLED_PIN,LOW);
    delay(100);
  }
}