Garrett 712120 VNT Hella 6NW 008 412 actuator.

GT2559V

187

10-29-2009, 05:01 PM #40

(10-29-2009, 02:12 PM)Tymbrymi Unfortunately, it DOES care about the frequency. Not sure what its range is, but I remember it didn't work at just any old frequency. I don't think it'll work on an analog voltage either.

You could always get a better PIC That definitely sucks though. It's annoying to have to bit-bang stuff when you have a hardware peripheral that should be able to do it.

Yep! But they're on my old phone, which I won't be able to get to till tonight. I'll try and post them if I get the chance.

Guess I'll just bit-bang it then, not too hard anyways, I can still use the timer to do most of the work.. I could get a better one, but what am I going to do with the stack of 18F14K22s I ordered for another scrapped project?? Undecided

Looking forward to those voltage readings before I try anything on the actuator.

EDIT: Any ideas on what the resolution of the actuator is? I kinda want to drop it down to 256 possible steps to get some cpu cycles back...

Heres the PWM code I worked up, seems to run ok in the simulator.

1000ms/7.119938ms = 140.45066Hz, should be close enough...

Code:

#include <p18cxxx.h>

#include "enc28j60.h"

#include "typedefs.h"

void init(void);

void pwm_init(void);

void isr_high(void);

void isr_low(void);

volatile BYTE pwm_duty_cycle = 128;

#define PWM_HIGH_STATE 0

#define PWM_LOW_STATE 1

/**************** INTERRUPTS ****************/

#pragma code high_vector=0x08

void interrupt_at_high_vector(void) {

    _asm GOTO isr_high _endasm

}

#pragma code

#pragma code low_vector=0x18

void interrupt_at_low_vector(void) {

    _asm GOTO isr_low _endasm

}

#pragma code

#pragma interrupt isr_high

void isr_high(void) {

    /**High Priority ISR**/

    /**Timer0 Overflow**/

    //TMR0L = 32;

    static BYTE pwm_num_ovrflw = 0;

    TMR0L = 40;

    if (pwm_num_ovrflw == pwm_duty_cycle) {

        // PWM Pin Low

        PORTCbits.RC5 = PWM_LOW_STATE;

    }else if (pwm_num_ovrflw == 0xFF) {

        pwm_num_ovrflw = 0;

        // PWM Pin High

        PORTCbits.RC5 = PWM_HIGH_STATE;

    }

    pwm_num_ovrflw++;

    //Clear Interrupt Flag

    INTCONbits.TMR0IF = 0;

}

#pragma interruptlow isr_low

void isr_low(void) {

    /**Low Priority ISR**/

}

/************** END INTERRUPTS **************/

void main (void) {

    init();

    while (1) {

        _asm NOP _endasm

    }

}

void init (void) {

    //Set Oscillator to 64MHz

    OSCCONbits.IRCF0 = 1;

    OSCCONbits.IRCF1 = 1;

    OSCCONbits.IRCF2 = 1;

    //Set Pin 12 Output High (Pin 12 is the power source for the level shifter)

    TRISBbits.TRISB5 = 0;

    PORTBbits.RB5 = 1;

    //Enable Interrupt Priority

    RCONbits.IPEN = 1;

    //Disable All Individual Interrupts

    INTCON = 0;

    INTCON3 = 0;

    //Set All Peripherial Interrupts = Disabled & Low Priority

    PIE1 = 0;

    IPR1 = 0;

    PIE2 = 0;

    IPR2 = 0;

    //Global High/Low Priority Interrupt Enable

    INTCONbits.GIEH = 1;

    INTCONbits.GIEL = 1;

    // Initialize the Ethernet Module

    //enc_init();

    // Start PWM Output

    pwm_init();

}

void pwm_init (void) {

    /*

    Timer0 PWM Setup

        Increment at 8MHz (0.125us)

        Overflow every 27.9017858us (35840Hz) (for 256 step PWM)

            = Increment 223.214286x Before Overflow

                -> Start Timer at 255-223 = 32

    */

    // Pin 5 as Output

    TRISCbits.TRISC5 = 0;

    // PWM Low

    PORTCbits.RC5 = PWM_LOW_STATE;

    //Disable Timer0

    T0CONbits.TMR0ON = 0;

    // 8-Bit Timer

    T0CONbits.T08BIT = 1;

    // Use Instruction Clock

    T0CONbits.T0CS = 0;

    // 1:2 Prescaler, 8MHz

    T0CONbits.PSA = 0;

    T0CONbits.T0PS0 = 0;

    T0CONbits.T0PS1 = 0;

    T0CONbits.T0PS2 = 0;

    // Enable Timer0 Overflow Interrupt

    INTCONbits.TMR0IF = 0;

    INTCONbits.TMR0IE = 1;

    //Enable Timer

    T0CONbits.TMR0ON = 1;

}

This post was last modified: 10-29-2009, 10:51 PM by 300SD81.

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