I am trying to send and receive data using I2C between an Arduino Nano and an ATTiny85. The ATTiny is mounted on this board: Link
I've tried to reach the slave with the simple I2C scanner, but I don't find anything.
Those are the codes:
Master (I2C scanner):
// --------------------------------------
// i2c_scanner
//
// Version 1
// This program (or code that looks like it)
// can be found in many places.
// For example on the Arduino.cc forum.
// The original author is not know.
// Version 2, Juni 2012, Using Arduino 1.0.1
// Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26 2013
// V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
// by Arduino.cc user Krodal.
// Changes by louarnold removed.
// Scanning addresses changed from 0...127 to 1...119,
// according to the i2c scanner by Nick Gammon
// http://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
// As version 4, but address scans now to 127.
// A sensor seems to use address 120.
// Version 6, November 27, 2015.
// Added waiting for the Leonardo serial communication.
//
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//
#include <Wire.h>
void setup()
{
Wire.begin();
Serial.begin(9600);
while (!Serial); // Leonardo: wait for serial monitor
Serial.println("\nI2C Scanner");
}
void loop()
{
byte error, address;
int nDevices;
Serial.println("Scanning...");
nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
Serial.print("I2C device found at address 0x");
if (address<16)
Serial.print("0");
Serial.print(address,HEX);
Serial.println(" !");
nDevices++;
}
else if (error==4)
{
Serial.print("Unknown error at address 0x");
if (address<16)
Serial.print("0");
Serial.println(address,HEX);
}
}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done\n");
delay(500); // wait 5 seconds for next scan
}
And this is the code of the ATTiny85 (slave):
#include <TinyWire.h>
#define led_pin 1
byte own_address = 10;
void setup() {
// config led_pin as Output for driving an LED
pinMode(led_pin, OUTPUT);
// config TinyWire library for I2C slave functionality
TinyWire.begin( own_address );
// sets callback for the event of a slave receive
TinyWire.onReceive( onI2CReceive );
}
void loop() {
}
/*
I2C Slave Receive Callback:
Note that this function is called from an interrupt routine and shouldn't take long to execute
*/
void onI2CReceive(int howMany){
// loops, until all received bytes are read
while(TinyWire.available()>0){
// toggles the led everytime, when an 'a' is received
if(TinyWire.read()=='a') digitalWrite(led_pin, !digitalRead(led_pin));
}
}
Once I've programmedo both the boards I've connected SCL and SCK pins of the boards together.
If i open the serial monitor of the master this is what i get:
I2C Scanner Scanning... Unknown error at address 0x20 Unknown error at address 0x21 No I2C devices found
Scanning... Unknown error at address 0x78 No I2C devices found
Scanning... No I2C devices found
Scanning... Unknown error at address 0x08 Unknown error at address 0x09 Unknown error at address 0x60 No I2C devices found
Scanning... Unknown error at address 0x70 No I2C devices found
And so on. Can someone explain me were I'm doing errors?