Pololu Simple User Manual

Page 95

{

command[0] = 0xA1;

command[1] = variableID;

sendBlocking(command, 2);

unsigned int response;

if (receiveBlocking((char *)&response, 2, 500))

return 0; // if we don't get a response in 500 ms, return 0

return response;

}

// initialization code called once when the program starts running

void setup()

{

setBaudRate(115200);

// briefly reset SMC when Arduino starts up (optional)

set_digital_output(resetPin, LOW);

delay_ms(1); // wait 1 ms

set_digital_input(resetPin, HIGH_IMPEDANCE); // let SMC run again

// must wait at least 1 ms after reset before transmitting

delay_ms(5);

// this lets us read the state of the SMC ERR pin (optional)

set_digital_input(errPin, HIGH_IMPEDANCE);

command[0] = 0xAA;

sendBlocking(command, 1); // send baud-indicator byte

setMotorLimit(FORWARD_ACCELERATION, 4);

setMotorLimit(REVERSE_ACCELERATION, 10);

setMotorLimit(DECELERATION, 20);

// clear the safe-start violation and let the motor run

exitSafeStart();

}

// main loop of the program; this executes over and over while the program runs

void loop()

{

static int speed = 3200; // full-speed forward

setMotorSpeed(speed);

speed = -speed; // switch motor direction

clear(); // clear the LCD and move cursor to start of first row

print("ts=");

// signed variables must be cast to ints:

print_long((int)getVariable(TARGET_SPEED));

lcd_goto_xy(0, 1); // move LCD cursor to start of second row

if (is_digital_input_high(errPin))

{

// if an error is stopping the motor, print the error status variable

// in hex and try to re-enable the motor

print("Err=");

print_hex(getVariable(ERROR_STATUS));

// once all other errors have been fixed, this lets the motor run again

exitSafeStart();

}

else

{

// print input voltage (in Volts) to the LCD

print("VIN=");

unsigned int vin = getVariable(INPUT_VOLTAGE);

// print truncated whole number of Volts

print_unsigned_long(vin/1000);

print_character('.');

// print rounded tenths of a Volt

print_unsigned_long(((vin%1000) + 50) / 100);

}

delay_ms(1000);

}

// program execution starts here

int main()

{

Pololu Simple Motor Controller User's Guide

6. Using the Serial Interface

Page 95 of 101