Controlling Jaguar with c code
 

I am using a jaguar for a different project. I am using an atmega32 as my micro controller for the project. I am not really sure how the jag uses the pwm to drive it.

Re: Controlling Jaguar with c code
 

A 50% duty cycle is mid-range, less than that is backwards, more than that is forwards. Is that what you were looking for?

HTH

Re: Controlling Jaguar with c code
 

Yes I think that should be all I need, I will get that set-up and tested tomorrow

Re: Controlling Jaguar with c code
 

That's not true. It uses a servo style PWM with expanded limits. See the jaguar datasheet at ti.com/jaguar for more details.

Re: Controlling Jaguar with c code
 

I see that in the data shee but I do not know how to code for a servo either. what i am running right now is not working.

Re: Controlling Jaguar with c code
 

This is the PWM code we are currently running



// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: 7.813 kHz
// Mode: Fast PWM top=0x00FF
// OC1A output: Non-Inv.
// OC1B output: Non-Inv.
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
TCCR1A=0xA1;
TCCR1B=0x0D;
TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0xFF;

// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: Timer2 Stopped
// Mode: Normal top=0xFF
// OC2 output: Disconnected
ASSR=0x00;
TCCR2=0x00;
TCNT2=0x00;
OCR2=0x00;

// External Interrupt(s) initialization
// INT0: Off
// INT1: Off
// INT2: Off
MCUCR=0x00;
MCUCSR=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x00;

// USART initialization
// Communication Parameters: 8 Data, 1 Stop, No Parity
// USART Receiver: On
// USART Transmitter: On
// USART Mode: Asynchronous
// USART Baud Rate: 9600
UCSRA=0x00;
UCSRB=0x18;
UCSRC=0x86;
UBRRH=0x00;
UBRRL=0x33;

// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;

// ADC initialization
// ADC disabled
ADCSRA=0x00;

// SPI initialization
// SPI disabled
SPCR=0x00;

// TWI initialization
// TWI disabled
TWCR=0x00;

while (1)
{
//XBEE Transmit & Receive
//delay_ms(10);

//PORTB = 0x1C;

USART_Receive();
//delay_ms(1000);

//PWM Drive Code
if(rxData == 0x31)
{
OCR1AL = 0x00; //set 0% duty cycle
//OCR1BL = 0x00; //set 0% duty cycle
}
else if(rxData == 0x33)
{
OCR1AL = 0x9E; //set 62% duty cycle
//OCR1BL = 0x66; //set 40% duty cycle
}
else if(rxData == 0x44)
{
OCR1AL = 0xB2; //set 70% duty cycle
//OCR1BL = 0x80; //set 50% duty cycle
}
else if(rxData == 0x55)
{
OCR1AL = 0xCC; //set 80% duty cycle
//OCR1BL = 0x9E; //set 62% duty cycle
}
else if(rxData == 0x66)
{
OCR1AL = 0xE6; //set 90% duty cycle
}
else if(rxData == 0x77)
{
OCR1AL = 0xFF; //set 100% duty cycle
}
//Reverse drive
else if(rxData == 0x35)
{
OCR1AL = 0x9E; //set 62% duty cycle
}
else if(rxData == 0x36)
{
OCR1AL = 0xB2; //set 70% duty cycle
}
else if(rxData == 0x37)
{
OCR1AL = 0xCC; //set 80% duty cycle
}
else if(rxData == 0x38)
{
OCR1AL = 0xE6; //set 90% duty cycle
}
else if(rxData == 0x39)
{
OCR1AL = 0xFF; //set 100% duty cycle
}
else
{
//OCR1AL = 0x00; //set 0% duty cycle
}

}
}

Re: Controlling Jaguar with c code
 

I stand corrected - sorry to give you bad advice (must have been thinking about model trains or something). The Jags use pulse widths, something like 1-2ms every 20ms.

Re: Controlling Jaguar with c code
 

Yeah we figured it out, set a Bunch of values up on a joystick and cycled through them until we got motion, by doing this we were able to find the range of inputs that the jaguars can accept.

Re: Controlling Jaguar with c code
 

well, perhaps not, I found a range where we get motion but we cannot seem to find where the middle/neutral is. a value from 12-48 is giving us full foraward or reverse so i figured somewhere in the middle should be neutral but i am not finding it.

Re: Controlling Jaguar with c code
 

If you'd rather not go through the trouble of producing the exact signals that the Jaguar takes by default, you can recalibrate the Jaguar to take the signal range that your output is delivering.

To do so:

If you want to reset the calibration to factory settings, just power up the Jaguar while holding down the USER button until a slow-flashing red and green pattern appears.

Re: Controlling Jaguar with c code
 

I have have an Arduino and I have just been using the regular old servo library for it and it runs great! I'm looking in the c file for that library and it says its minimum pulse width is 544 and its max is 2400 in microseconds, default says it is 1500.

Re: Controlling Jaguar with c code
 

Well we got to the the code on our bot today and it works....sometimes. Without changing the values it would move sometimes and not others I am at a bit of a loss as to what is going on. I don't see how the same value is producing different results.

Re: Controlling Jaguar with c code
 

which pwm frequency do I want? 7k or 31k?

Re: Controlling Jaguar with c code
 

try 50Hz rep rate of 1-2 mS positive pulse 0-5v

20 ms period = 50 Hz PWM frequency but this can vary and is NOT critical

kHz may be way too high might produce weird result such as you have

traditional PWM R/C signal is 1ms to 2ms with 1.5ms as neutral.

Servos swing 90 degrees on either side of neutral

-90 deg = 1 mS
neutral = 1.5mS (define a +-few% say 20 - 40 us deadband to avoid chatter)
+90deg = 2.0 mS

For a 555 based hardware driver solution:
http://pcbheaven.com/wikipages/How_RC_Servos_Works/

Re: Controlling Jaguar with c code
 

I just finished messing around with this...
https://sites.google.com/site/0123ic..._jaguar/jagwii
Control a Jaguar with a WiiNunchuck through the Arduino Platform

https://sites.google.com/site/0123ic...arduino_jaguar
has code with references at the bottom of the page