uint8_t i2c_do(i2c_struct *i2c)
{
for(;;)
{
i2c_step(i2c);
if ( i2c->state == I2C_STATE_NONE )
return 1;
if ( i2c->state == I2C_STATE_ERROR )
return 0;
}
}
// Interrupt service routine to handle the compass communications
void __ISR_COMPASS_I2C(void) // Called at 24896Hz
{
// I2C clock stretching
if(i2c_scl_read() != g_i2c_scl_cmd)
return;
// Step the low level FSM
i2c_step();
// Retrieve the current high level FSM command
const struct Command* cmd = &g_script[current_entry];
// Perform the required action for the command
switch(cmd->type)
{
// Signal a start condition
case CMD_START:
if(g_i2c_state == I2C_IDLE)
i2c_start();
else if(g_i2c_state == I2C_READY)
current_entry++;
break;
// Write a byte of data
case CMD_WRITE:
switch(g_i2c_state)
{
case I2C_READY:
i2c_write(cmd->data);
break;
case I2C_WRITE_GOT_ACK:
g_i2c_state = I2C_READY;
current_entry++;
break;
case I2C_WRITE_GOT_NACK:
g_i2c_state = I2C_READY;
current_entry++;
break;
default:
break;
}
break;
// Read a byte of data
case CMD_READ:
switch(g_i2c_state)
{
case I2C_READY:
i2c_read();
break;
case I2C_READ_ENDED:
read_data[cmd->data] = g_i2c_read;
g_i2c_state = I2C_READY;
current_entry++;
break;
default:
break;
}
break;
// Signal a stop condition
case CMD_STOP:
if(g_i2c_state == I2C_READY)
i2c_stop();
else if(g_i2c_state == I2C_IDLE)
current_entry++;
break;
// Process the last read data and loop back to a particular command (zero-based index in g_script)
case CMD_LOOP:
ProcessData();
current_entry = cmd->data;
break;
// Wait some time
case CMD_WAIT:
if(wait_counter == 0)
wait_counter = cmd->data;
else if(wait_counter == 1)
{
wait_counter = 0;
current_entry++;
}
else
wait_counter--;
break;
// Should never happen
default:
break;
}
}
