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uint8_t eeprom_read(uint16_t address, void* buf, uint16_t count)
{
   uint8_t *b = buf;
   I2C_START;
   uint8_t ack = i2c_write(EEPROM_ADDRESS);
   if (ack) {
      I2C_STOP;
      return ack;
   }
   ack = i2c_write(address >> 8);
   if (ack) {
      I2C_STOP;
      return ack;
   }
   ack = i2c_write(address & 0xFF);
   if (ack) {
      I2C_STOP;
      return ack;
   }
   I2C_STOP;
   I2C_START;
   ack = i2c_write(EEPROM_ADDRESS | 1);
   if (ack) {
      I2C_STOP;
      return ack;
   }
   while (count) {
      *b = i2c_read(count > 1);
      b++;
      count--;
   }
   I2C_STOP;
   return ack;
}

uint8_t eeprom_write(uint16_t address, void* buf, uint16_t count)
{
   uint8_t *b = buf;
   uint8_t ack = 0;
   while (count) {
      PORTC ^= 2;
      uint8_t nbytes = 64 - (address & 63);
      if (nbytes > count) nbytes = count;
      uint8_t attempts = 100;
      while (attempts--) {
         I2C_START;
         ack = i2c_write(EEPROM_ADDRESS);
         if (!ack) break;
         else I2C_STOP;
      }
      if (ack) {
         return ack;
      }
      ack = i2c_write(address >> 8);
      if (ack) {
         I2C_STOP;
         return ack;
      }
      ack = i2c_write(address & 0xFF);
      if (ack) {
         I2C_STOP;
         return ack;
      }
      count -= nbytes;
      while (nbytes) {
         ack = i2c_write(*b);
         if (ack) {
            I2C_STOP;
            return ack;
         }
         b++;
         nbytes--;
      }
      I2C_STOP;
      address += nbytes;
   }
   uint8_t attempts = 100;
   while (attempts--) {
      I2C_START;
      uint8_t ack = i2c_write(EEPROM_ADDRESS);
      I2C_STOP;
      if (!ack) break;
   }
   return ack;
}

uint8_t buf[8] = {
   1, 2, 3, 4, 5, 6, 7,
};

FILE serial = FDEV_SETUP_STREAM(fputchar, NULL, _FDEV_SETUP_WRITE);

int main(void)
{
   stdout = &serial;
   UBRRH = 0;
   UBRRL = 197;
   DDRD = (1 << 1); // TXD
   DDRC = 2;        // debug
   UCSRB = (1 << TXEN);
   if (eeprom_write(0, buf, 8)) printf("WRITE FAIL!\n\n");
   if (!eeprom_read(0, buf, 8)) {
      printf("%02X ", buf[0]);
      printf("%02X ", buf[1]);
      printf("%02X ", buf[2]);
      printf("%02X ", buf[3]);
      printf("%02X ", buf[4]);
      printf("%02X ", buf[5]);
      printf("%02X ", buf[6]);
      printf("%02X\n", buf[7]);
   }
   for(;;);
}

#define I2C_STOP {PULL_SCL; I2C_DELAY; RELEASE_SCL;  I2C_DELAY; RELEASE_SDA; I2C_DELAY;}

#define I2C_STOP {PULL_SCL; PULL_SDA; I2C_DELAY; RELEASE_SCL;  I2C_DELAY; RELEASE_SDA; I2C_DELAY;}