back in 2005 i programmed the atmega168 to control servos . . . but at that time gcc was buggy and there was like no source code for it on the web . . . so my code was all ugly and hacked together from a total lack of understanding of why my code even worked (yea, it worked!) . . . this is what happens when you let a mechanical engineer program . . .
anyway, here is the atmega168 source code for others to use:
#include <avr/io.h>
//#include <avr/interrupt.h>
//#include <string.h>
//***************DELAY CODE**************
//delay exactly 1 clock cycle
void delay_cycles(unsigned int timed) {
while(timed>0)
timed--;
return;
}
//****************************************
//*************************BEEPER CODE**********************
//beep for cycle time at certain frequency
void beep (unsigned int cycles, unsigned int freq) {
DDRB |= 1<<PB0; //make PB0 an output
long i;
while (cycles > 0) {
PORTB |= 1<<PB0; // buzzer pin high
for(i=0;i<freq;i++);
PORTB &= !(1<<PB0); // buzzer pin low
for(i=0;i<freq;i++);
cycles--;
}
return;
}
//**********************************************************
//*****required for ADC conversion (screws up everything!)
/*
//this came from the main:
//usart_putchar(ADCL);
//******end of ADC code
*/
//main function, begins with initialization
//NOTE servo actuation code does not work outside of main for some odd reason
int main(void) {
#include <servoPositions.h>//this include ONLY works in main cause the compiler sucks like that
unsigned int step=0;
unsigned int i=0;
//DDRn Data Direction Registers (0 for input vs 1 for output)
//DDRC = 0xFF; //configure all ports for output
//DDRC = 0x00; //configure all ports for input
//pull up resistors generally good for inputs
//PORTC = 0xFF; //turns pullup resistors on for all C ports
//PORTC = 0x00; //turns pullup resistors off for all C ports
//DDRD |= 1<<PD1; // OR set PD1 to output
//DDRC |= 1<<PC3; // OR set PC3 to output
//DDRC |= 0<<PC6;//set ADC6 to input
//PORTC |= 1<<PC6;//turn on ADC6 pullup resistor
/*
//ADC init
ADMUX = 0; // channel 0 //ADC init
ADCSRA |= _BV(ADEN) | _BV(ADPS1) | _BV(ADPS2);//ADC init
ADCSRA |= _BV(ADSC);//ADC Start Conversion
//!(ADCSRA & _BV(ADIF));//ADC wait for conversion
//ADCSRA |= _BV(ADIF);//ADC clear ADIF
//if(ADCL>200)
//beep(1500,28);
*/
beep(1500, 25);
DDRC |= 0x7C; //setup portC for output 0b1111100 (PC0-PC5)
//DDRC |= 0x3 //setup portC for input 0b0000011 (PC6-PC7)
//motor1table[4]=100;
PORTC &= !(1<<PC5);//initialize PWM off
while(1) {
i=0;
//delay_cycles(3000);
while(i<7) {
//step=7;
//***************SERVO ACTUATION CODE***************
//accepts a time in clock cycles to pulse each servo
PORTC |= 1<<PC3; //servo 1
delay_cycles(servo1table[step]);
PORTC &= !(1<<PC3);
PORTC |= 1<<PC2; //servo 2
delay_cycles(servo2table[step]);
PORTC &= !(1<<PC2);
PORTC |= 1<<PC1; //servo 3
delay_cycles(servo3table[step]);
PORTC &= !(1<<PC1);
PORTC |= 1<<PC0; //servo 4
delay_cycles(servo4table[step]);
PORTC &= !(1<<PC0);
PORTC |= 1<<PC4; //servo 5
delay_cycles(servo5table[step]);
PORTC &= !(1<<PC4);
/*
PORTC |= 1<<PC5; //motor 1
delay_cycles(motor1table[step]);
PORTC &= !(1<<PC5);*/
//**************************************************
//delay_cycles(100);
i++;
}
//in future, have it ++ only if the encoder detects a change in position
// -also have it reset to 0 if it detects restart mark
step++;//step=0;
if (step>=8) {
//beep(1500, 25);//step=0;
step=0;
}
/*
PORTD |= 1<<PD1; // LED on
for(i=0;i<10000;i++);
PORTD &= !(1<<PD1); // LED off
for(i=0;i<10000;i++);*/
}
return 0;
}
now for my questions . . .
looking at Dave Hyland's code, i have a few questions that will help me port this over to the atmega644:
(
atmega128 datasheet for reference)
im kinda confused what this code does
#define RED_LED_PIN 4
#define RED_LED_MASK ( 1 << RED_LED_PIN )
#define RED_LED_DDR DDRG
#define RED_LED_PORT PORTG
RED_LED_DDR |= RED_LED_MASK;
what i think the last line is saying is this:
DDRG |= 1 << 4;
which i think means configure port PG4 to output, right?
also this code . . .
#define LED_ON( color ) color ## _LED_PORT &= ~color ## _LED_MASK
#define LED_OFF( color ) color ## _LED_PORT |= color ## _LED_MASK
what i think this is saying is when I write LED_ON( RED ) in my main, it changes to this:
PORTG &= 1 << 4;
which i think means set PG4 to 0 (if i did PORTG |= 1 << 4 , this would set the pin to 1), right?
what is the difference between these? i think this might clear up my confusion . . .
PORTG &= !(1 << 4);
PORTG |= !(1 << 4);
PORTG &= 1 << 4;//sets PG4 to 1
PORTG |= 1 << 4;
also, im looking at the
AVRlib for AVR . . . quite possibly a dumb question . . . i just copy/paste the functions from the c files and put into my code, right? then i just include the .h files and it will work, right? believe it or not it took me like 20 min of confusion to figure that out . . .
and a link to dunks new
USB Servo Controller Tutorial (thanks, dunk!!! im already putting some of it to use)
(edit: changed dunk's link)
