Arduino Jaguar
This page has details on running a USFIRST FRC jaguar from an Arduino
The Adaptor Board is available at: http://www.sparkfun.com/products/9281
First step involved speed control via the serial link.
//
#include <avr/interrupt.h>
const int jagsigpin = 9; //pwm connection on pin 9
const int jagpwrpin = 7;//using pin 7 as the pwm power reference
const int jaggndpin = 8;//using pin 8 as the pwm ground reference
const int ledpin = 13;//using the standard LED as a status indicator
const int buffsize = 3;//determining the digits buffer size
char mybuffer[buffsize]; //declare an array to take input from the serial
int value = 47;// decimal 47 corresponds with the pwm midpoint
int minvalue = 20;// decimal 20 corresponds with the pwm full reverse
int maxvalue = 74; //decimal 74 corresponds with the pwm full forward
boolean ledstatus = LOW; //initialize the LED status
void setup()
{
//set the PWM frequency to be 122Hz
TCCR1B = TCCR1B & 0b11111000 | 0x04;
//setup the pins to be used with the PWM
pinMode(jagsigpin, OUTPUT);
pinMode(jagpwrpin, OUTPUT);
pinMode(jaggndpin, OUTPUT);
//setup the LED status pin
pinMode(ledpin, OUTPUT);
//define the pwm reference voltages
digitalWrite(jagpwrpin,HIGH);
digitalWrite(jaggndpin,LOW);
//start the serial interface... 9600 is arbitrary
Serial.begin(9600);
//set the pwm to midscale so the jaguar starts in a friendly state
analogWrite(jagsigpin,value);
}
void loop(){
//wait for there to be something on the serial interface
if(Serial.available()>0){
// give time for the rest of the digits to come across
delay(100);
// 8bit characters (chars) come across the serial interface, each one is an ascii value
// group these characters into a char array for processing
for(int i =0; i<buffsize; i=i+1){
mybuffer[i] = Serial.read();
}
Serial.flush();
//use the c function "atoi" to convert the char array to a integer value
value = atoi(mybuffer);
// print the value to the console
Serial.print(value);
//write the pwm value
analogWrite(jagsigpin,value);
//toggle the indicator
ledstatus = ~ledstatus;
digitalWrite(ledpin,ledstatus);
Serial.write('\n');
}
}
References:
Changing the Arduino PWM frequency
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1235060559/0#4
Page 5, Table 4 has the PWM timing information
Autoramp mode was necessary to not trip the overcurrent protection on my bench power supplies
Check out Q7 for Details on enabling:
