I tried library, even on real SDA and SCL pins, but it doesn't work.

What am I doing wrong? (All connections is fine, because hardware TWI works but software not.) Thank you for your help.

(Fuses are ok, because the Atmega won't response if I remove the crystal oscillator, LED blinking duration is ok.)

I tried this library, even on real SDA and SCL pins, but it doesn't work.

What am I doing wrong? (All connections is fine, because hardware TWI works but software does not.) Thank you for your help.

(Fuses are ok, because the Atmega won't respond if I remove the crystal oscillator, the LED blinking duration is ok.)

I am using Atmega8 with 12MHz crystal, on my breadbord. I can use SDA and SCL pins with default arduino library wire.h, and it works. But I want another pins to use I²C protocol.

(Fuses are ok, because Atmega won't response if I remove the crystal oscillator, LED blinking duration is ok.)

Except instead of 16MHz, I use 12MHz and ch210x serial.

I am using ATmega8 with 12MHz crystal, on my breadboard. I can use SDA and SCL pins with default arduino library wire.h, and it works. But I want another pins to use I²C protocol.

(Fuses are ok, because the Atmega won't response if I remove the crystal oscillator, LED blinking duration is ok.)

Except instead of 16MHz, I use a 12MHz and ch210x serial.

I am using Atmega8 with 12MHz crystal, on my breadbord. I can use SDA and SCL pins with default arduino library wire.h, and it works. But I want another pins to use I²C protocol.

I tried library, even on real SDA and SCL pins, but it doesn't work.

I have pull up resistors, I tried with 10k and 4.7k without any success. ( But those resistors worked hardware I²C |TWI)

What am I doing wrong? ( All connections is fine, because hardware TWI works but software not.  ) Thank you for your help.

( Fuses are ok, because Atmega won't response if I remove the crystal oscillator, LED blinking duration is ok. )

what i want to run : ( that doesnt work )

#define SDA_PORT PORTC
#define SDA_PIN 4
#define SCL_PORT PORTC
#define SCL_PIN 5

//#define I2C_TIMEOUT 100

#include <SoftI2CMaster.h>


uint8_t ADDR  = 0x68;

void setup(void) {

  Serial.begin(19200);
  Serial.println("Initializing ...");
  i2c_init();

  if (!i2c_start(ADDR | I2C_WRITE)) Serial.println(F("Device does not respond"));
  if (!i2c_write(0x00)) Serial.println(F("Cannot address reg 0"));
  i2c_stop();
}  

void loop (void) {
  unsigned int low0, high0, low1, high1;
  unsigned int chan0, chan1;
  unsigned int lux;
  int state1;
  int state2;

  delay(1000);
  i2c_start(ADDR | I2C_WRITE);
  i2c_write(0x00);
  i2c_rep_start(ADDR | I2C_READ);
  low0 = i2c_read(false);
  high0 = i2c_read(false);
  low1 = i2c_read(false);
  high1 = i2c_read(true);
  i2c_stop();
  Serial.print(low0);
}

What the hardware twi that works  :

Schematic is the same as  : https://www.arduino.cc/en/main/standalone

except 16mhz, i use 12mhz and ch210x serial

arduino's bootloader works well, i compiled from source.

I am using Atmega8 with 12MHz crystal, on my breadbord. I can use SDA and SCL pins with default arduino library wire.h, and it works. But I want another pins to use I²C protocol.

I tried library, even on real SDA and SCL pins, but it doesn't work.

I have pull up resistors, I tried with 10k and 4.7k without any success. (But those resistors worked with hardware I²C | TWI)

What am I doing wrong? (All connections is fine, because hardware TWI works but software not.) Thank you for your help.

(Fuses are ok, because Atmega won't response if I remove the crystal oscillator, LED blinking duration is ok.)

What i want to run (that doesn't work):

#define SDA_PORT PORTC
#define SDA_PIN 4
#define SCL_PORT PORTC
#define SCL_PIN 5

//#define I2C_TIMEOUT 100

#include <SoftI2CMaster.h>


uint8_t ADDR  = 0x68;

void setup(void) {

  Serial.begin(19200);
  Serial.println("Initializing ...");
  i2c_init();

  if (!i2c_start(ADDR | I2C_WRITE)) Serial.println(F("Device does not respond"));
  if (!i2c_write(0x00)) Serial.println(F("Cannot address reg 0"));
  i2c_stop();
}  

void loop (void) {
  unsigned int low0, high0, low1, high1;
  unsigned int chan0, chan1;
  unsigned int lux;
  int state1;
  int state2;

  delay(1000);
  i2c_start(ADDR | I2C_WRITE);
  i2c_write(0x00);
  i2c_rep_start(ADDR | I2C_READ);
  low0 = i2c_read(false);
  high0 = i2c_read(false);
  low1 = i2c_read(false);
  high1 = i2c_read(true);
  i2c_stop();
  Serial.print(low0);
}

And the code with hardware TWI that works:

Schematic is the same as: https://www.arduino.cc/en/main/standalone.

Except instead of 16MHz, I use 12MHz and ch210x serial.

Arduino's bootloader works well, I compiled it from source.