void i2c_stop(unsigned char state) {
TWCR = _BV(TWINT) | _BV(TWEN) | _BV(TWSTO); // Завершение передача
i2c_state = I2C_STATE_STOPPING;
if (i2c_callback != 0) {
if (i2c_callback(state)){
// Повторное выполнение запроса
i2c_result_end_pos = i2c_buf_pos = i2c_result_pos = 0;
i2c_end_of_block = i2c_buf[i2c_buf_pos++] + 1;
TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN) | _BV(TWIE); // Send START condition.
return;
}
}
sei();
timer1PutTask(2, &set_free, 0); // Задержка примерно 1/62500 * 30 секунды
}
static void i2c_irq_handler(unsigned irq) {
//i2c state machine.
//printf("I2C irq handler\n");
//first let's make sure nothing is f'ed up
//TODO: uncomment this error checking when we have some way to handle errors
// if(((i2c_regs->cmd_status & I2C_ST_RXACK) != 0) && i2c_dir == I2C_DIR_WRITE) { //we got a NACK and we didn't send it
// printf("\tNACK received\n");
// i2c_async_err();
// return;
// }// else printf("\tACK received, proceeding\n");
if(i2c_regs->cmd_status & I2C_ST_AL) {
printf("\tArbitration lost!\n");
i2c_async_err();
return;
}
if(i2c_regs->cmd_status & I2C_ST_TIP) {
//printf("\tI2C still busy in interrupt\n");
return;
}
//now decide what to do
switch(i2c_state) {
case I2C_STATE_IDLE:
//this is an error. in idle state, we shouldn't be transferring data, and the fact that the IRQ fired is terrible bad.
printf("AAAAAHHHHH INTERRUPT IN THE IDLE STATE AAAHHHHHHHHH\n");
i2c_async_err();
break;
case I2C_STATE_CONTROL_BYTE_SENT: //here we've sent the control byte, and we're either clocking data in or out now, but we haven't received a byte yet.
case I2C_STATE_DATA: //here we're sending/receiving data and if we're receiving there's data in the data reg
//if(i2c_state == I2C_STATE_DATA) printf("\tI2C in state DATA with dir=%d and len=%d\n", i2c_dir, i2c_len);
//else printf("\tI2C in state CONTROL_BYTE_SENT with dir=%d and len=%d\n", i2c_dir, i2c_len);
if(i2c_dir == I2C_DIR_READ) {
if(i2c_state == I2C_STATE_DATA) *(i2c_bufptr++) = i2c_regs->data;
//printf("\tRead %x\n", *(i2c_bufptr-1));
//set up another data byte
if(i2c_len > 1) //only one more byte to transfer
i2c_regs->cmd_status = I2C_CMD_RD;
else
i2c_regs->cmd_status = I2C_CMD_RD | I2C_CMD_NACK | I2C_CMD_STOP;
}
else if(i2c_dir == I2C_DIR_WRITE) {
//write a byte
//printf("\tWriting %x\n", *i2c_bufptr);
i2c_regs->data = *(i2c_bufptr++);
if(i2c_len > 1)
i2c_regs->cmd_status = I2C_CMD_WR;
else {
//printf("\tGenerating STOP\n");
i2c_regs->cmd_status = I2C_CMD_WR | I2C_CMD_STOP;
}
};
i2c_len--;
if(i2c_len == 0) i2c_state = I2C_STATE_LAST_BYTE;
else i2c_state = I2C_STATE_DATA; //takes care of the addr_sent->data transition
break;
case I2C_STATE_LAST_BYTE: //here we've already sent the last read request and the last data is waiting for us.
//printf("\tI2C in state LAST BYTE\n");
if(i2c_dir == I2C_DIR_READ) {
*(i2c_bufptr++) = i2c_regs->data;
//printf("\tRead %x\n", *(i2c_bufptr-1));
i2c_state = I2C_STATE_DATA_READY;
} else {
i2c_state = I2C_STATE_IDLE;
}
i2c_regs->ctrl &= ~I2C_CTRL_IE; //disable interrupts until next time
if(i2c_callback) {
i2c_callback(); //if we registered a callback, call it!
}
break;
default: //terrible things have happened.
break;
}
}
