[Flashforth-devel] PWM at PIC18F2620

[Thomas B. <bus...@gm...>]

Hallo FFFans,

I try to run PWM on a PIC18F2620 with no success (I dont see any spike in
the logic analyzer). Here are my parameters:

Tosc 8 MHz
Periode: 36 KHz
Duty Cycle: 25%
Output is RB3/CCP2 Pin24
Pre- Postscaler: 1

And here my Programm:

-pwm
marker -pwm
$ff81 constant portb
$ff93 constant trisb
$ffba constant ccp2con
$ffcb constant pr2
$ffbb constant ccpr2l
$ffcc constant tmr2
$ffca constant t2con

: init
\ Set the PWM period by writing to the PR2 register.
%00110110 pr2 c! \ #54 Periode: 0,0000275 s / Prescaler: 1 / Tosc: 8MHz
\ Set PWM dutycycle to the CCPR2L register and CCP2CON<5:4> bits
\ dutycyle: 25% = #56 (10bit) = %0000 1110 00
%00001110 ccpr2l c!
%00110000 ccp2con mclr
\ Make the CCP2 pin an output by clearing the appropriate TRIS bit.
\ RB3/CCP2 output
%00000100 trisb mclr
\ Set the TMR2 prescale value, then enable Timer2 by writing to T2CON.
0 tmr2 c! \ reset tmr2
%00000100 t2con c! \ prescale 1, timer2 is on
\ Configure the CCPx module for PWM operation.
%00001100 ccp2con c!
;

What I missed ?

Thank you for looking.
Thomas
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