Pololu 3pi Robot - Manual (Page 52)

}
// Returns true if and only if the byte is a data byte (< 0x80).
char is_data(char byte)
{
if (byte < 0)
return 0;
return 1;
}
// If it's not a data byte, beeps, backs up one, and returns true.
char check_data_byte(char byte)
{
if(is_data(byte))
return 0;
play("o3c");
clear();
print("Bad data");
lcd_goto_xy(0,1);
print_hex_byte(byte);
previous_byte();
return 1;
}
/////////////////////////////////////////////////////////////////////
// COMMAND FUNCTIONS
//
// Each function in this section corresponds to a single serial
// command. The functions are expected to do their own argument
// handling using read_next_byte() and check_data_byte().
// Sends the version of the slave code that is running.
// This function also shuts down the motors and disables PID, so it is
// useful as an initial command.
void send_signature()
{
serial_send_blocking("3pi1.0", 6);
set_motors(0,0);
pid_enabled = 0;
}
// Reads the line sensors and sends their values. This function can
// do either calibrated or uncalibrated readings. When doing calibrated readings,
// it only performs a new reading if we are not in PID mode. Otherwise, it sends
// the most recent result immediately.
void send_sensor_values(char calibrated)
{
if(calibrated)
{
if(!pid_enabled)
read_line_sensors_calibrated(sensors, IR_EMITTERS_ON);
}
else
read_line_sensors(sensors, IR_EMITTERS_ON);
serial_send_blocking((char *)sensors, 10);
}
// Sends the raw (uncalibrated) sensor values.
void send_raw_sensor_values()
{
send_sensor_values(0);
}
// Sends the calibated sensor values.
void send_calibrated_sensor_values()
{
send_sensor_values(1);
}
// Computes the position of a black line using the read_line()
// function, and sends the value.
// Returns the last value computed if PID is running.
void send_line_position()
{
Pololu 3pi Robot User's Guide © 2001–2014 Pololu Corporation
10. Expansion Information Page 52 of 63