18F4431 Quaduature Encoder

[HenrikOlsson]

Hi Bruce,
Thank you for info regarding RE3/MCLR as input.

It sure is a cool device. Using Darrel's interupt routines I managed to get motor controller for my robot working, with PID filter and all. Very fun project.

However.....I never managed to get QEI module going in velocity mode. I made a few attempts to begin with but could never quite figure it out so I went for my own velocity calcs (newPos-oldPos). Any pointers?

Thanks!
/Henrik Olsson.

[Bruce]

Hi Henrik,

I haven't messed with QEI yet, but if I do get something going, I'll port it from C to PBP and post it here.

My primary interest in this one was the new high-speed A/D, and motion feedback module for background pulse & freq measurements.

[HenrikOlsson]

Bruce,
I see. Thanks anyway!

/Henrik Olsson.

[hell_pk]

Hi!
i got hold of Microchip PICDEm MC LV board with 3-phase BLDC motor.It has a CD that conatins source code in assembly. I was wondering if someone has done same thing in pic basic i.e used power PWM module of 18F4431.I tried according to application note but to no avail. Here is my code.could someone point me out in right direction.some code snipet would be appreciated.
thanks

while true
PTCON0=00000000 'page 8,step 1
PTPERL=$37 'a guess
PTPERH=$01
PWMCON0=01001111 'step 3
PWMCON1=00000001 'step 4
DTCON=00000000 ' a guess
OVDCOND=00000000 'step 6
OVDCONS=00000000
FLTCONFIG=00000000
'POVD=00000000
'SEVTCMP=$0000
'step 8
SEVTCMPL=$00
SEVTCMPH=$00
PDC0L=$00
PDC0H=$00
PDC1L=$00
PDC1H=$00
PDC2L=$00
PDC2H=$00
PDC3L=$00
PDC3H=$00


TRISC.0=1
PTCON1=10000000 'or PTCON1.7=1
wend

[hell_pk]

Hi!
i got hold of Microchip PICDEm MC LV board with 3-phase BLDC motor.It has a CD that conatins source code in assembly. I was wondering if someone has done same thing in pic basic i.e used power PWM module of 18F4431.I tried according to application note but to no avail. Here is my code.could someone point me out in right direction.some code snipet would be appreciated.
thanks

while true
PTCON0=00000000 'page 8,step 1
PTPERL=$37 'a guess
PTPERH=$01
PWMCON0=01001111 'step 3
PWMCON1=00000001 'step 4
DTCON=00000000 ' a guess
OVDCOND=00000000 'step 6
OVDCONS=00000000
FLTCONFIG=00000000
'POVD=00000000
'SEVTCMP=$0000
'step 8
SEVTCMPL=$00
SEVTCMPH=$00
PDC0L=$00
PDC0H=$00
PDC1L=$00
PDC1H=$00
PDC2L=$00
PDC2H=$00
PDC3L=$00
PDC3H=$00


TRISC.0=1
PTCON1=10000000 'or PTCON1.7=1
wend

[Rleonard]

I wish I could help but I am using the 18F4431 in a completely
different manner.
Richard

[Bruce]

I don't have the 18F4431 or Microchip motor control board, but this works
on the 18F2431. It outputs PWM on RB0,RB1,RB2,RB3,RB4 and RB5 with a
varying duty cycle. Ramps up, then down.

It should be at least enough to get you started.

    DEFINE OSC 20
    
    Duty VAR WORD
    PORTB = $FF
    TRISB = 0
    
    PTCON0=$00 'page 8,step 1
    PTPERL=$A0      ' $01A0 = 12kHz
    PTPERH=$01
    PWMCON0=%01011110 'would be %01011111 for the 18F4431
    PWMCON1=%00000001 'step 4
    DTCON=$00
    ;OVDCOND=$00 'step 6  ; May want to un-comment these based on your PIC & board.
    ;OVDCONS=$00
    ;FLTCONFIG=%10110011
    ;POVD=00000000
    ;SEVTCMP=$0000
    ;step 8
    SEVTCMPL=$00
    SEVTCMPH=$00
    PDC0L=$00
    PDC0H=$00
    PDC1L=$00
    PDC1H=$00
    PDC2L=$00
    PDC2H=$00
    ;PDC3L=$FF ; un-comment for 18F4431
    ;PDC3H=$00
    PTCON1=%10000000
    
Main:
    FOR Duty = 50 TO $500 STEP 4
        ASM
        bsf   PWMCON1,UDIS	    ;Disable the PWM buffer update
        MOVFF _Duty,PDC0L
        MOVFF _Duty+1,PDC0H
        MOVFF _Duty,PDC1L
        MOVFF _Duty+1,PDC1H
        MOVFF _Duty,PDC2L
        MOVFF _Duty+1,PDC2H
        ;MOVFF _Duty,PDC3L      ;un-comment for 18F4431
        ;MOVFF _Duty+1,PDC3H
        bcf	  PWMCON1,UDIS	    ;Enable the PWM buffer update
        ENDASM
        PAUSE 50
    NEXT Duty
    FOR Duty = $500 TO 50 STEP-4
        ASM
        bsf	  PWMCON1,UDIS	    ;Disable the PWM buffer update
        MOVFF _Duty,PDC0L
        MOVFF _Duty+1,PDC0H
        MOVFF _Duty,PDC1L
        MOVFF _Duty+1,PDC1H
        MOVFF _Duty,PDC2L
        MOVFF _Duty+1,PDC2H
        ;MOVFF _Duty,PDC3L      ;un-comment for 18F4431
        ;MOVFF _Duty+1,PDC3H
        bcf	  PWMCON1,UDIS	    ;Enable the PWM buffer update
        ENDASM
        PAUSE 50
    NEXT Duty
    GOTO Main
    
    END

This is just a slight modification to what you posted before. To work with the
18F2431. I haven't done much beyond this with the PCPWM module. Not yet
at least..;o}

HTH

[BigWumpus]

I'm using the 18F2431 too.
And I begun with the PICDEm MC LV board...

It's a great uC ! (UART, I2C, fast AD, 3-times PWM...)
I use it as a PI(D)-Controller for a BLDC-Motor.
And I use it for his fast AD-Converters in a CR-Tuning-Box.

The Quadrature-Encoder isn't very strange ... the whole business with this chip is to use the right timers for the right tasks and use the right prescalers !!

;-)