//
// hello.servo.44.c
//
// servo motor hello-world
//
// set lfuse to 0x7E for 20 MHz xtal
//
// Neil Gershenfeld
// 4/8/12
//
// (c) Massachusetts Institute of Technology 2012
// Permission granted for experimental and personal use;
// license for commercial sale available from MIT.
//
#include
#include
#define output(directions,pin) (directions |= pin) // set port direction for output
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
#define position_delay() _delay_ms(500)
#define PWM_port PORTA
#define PWM_pin (1 << PA6)
#define PWM_direction DDRA
int main(void) {
//
// main
//
// set clock divider to /1
//
CLKPR = (1 << CLKPCE);
CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
//
// set up timer 1
//
TCCR1A = (1 << COM1A1) | (0 << COM1A0); // clear OC1A on compare match
TCCR1B = (0 << CS12) | (1 << CS11) | (0 << CS10) | (1 << WGM13); // prescaler /8, phase and frequency correct PWM, ICR1 TOP
ICR1 = 25000; // 20 ms frequency
//
// set PWM pin to output
//
clear(PWM_port, PWM_pin);
output(PWM_direction, PWM_pin);
//
// main loop
//
while (1) {
//
// 1 ms PWM on time
//
OCR1A = 500;
position_delay();
//
// 1.5 ms PWM on time
//
OCR1A = 1000;
position_delay();
//
// 2 ms PWM on time
//
OCR1A = 1200;
position_delay();
}
}