Probleem instellen PWM frequentie 16F628

procedure init_PWM is
   f877_pr2 = 255 -- Tmr2 period reg: PWM period = (PR2+1).4.Tosc.(Tmr2_prescale)
   -- CCP1
   f877_ccpr1l = 0
   pin_c2_direction = output
   f877_t2con = 0b_0000_0100 -- Tmr2 on, prescaler = 1
   f877_ccp1con = 0b_0000_0000
   pin_c2 = low
   -- CCP2
   f877_ccpr2l = 0
   pin_c1_direction = output
   f877_t2con = 0b_0000_0100 -- Tmr2 on, prescaler = 1	
   f877_ccp2con = 0b_0000_0000
   pin_c1 = low
end procedure

-- Fan 1(left) on RC2 / CCP1

procedure start_fan_left ( byte in out dutycycle, bit out on_off, bit out start ) is
   if dutycycle < 200 then
      f877_ccpr1l = 200
      start = true
      if dutycycle < 155 then
         dutycycle = 155
      end if
   else
      f877_ccpr1l = dutycycle
   end if
   f877_ccp1con = 0b_0011_1100
   on_off = true
end procedure

procedure stop_fan_left ( byte out dutycycle, bit out on_off, bit out start ) is
   dutycycle = 0
   f877_ccpr1l = dutycycle
   f877_ccp1con = 0b_0000_0000
   pin_c2 = low
   on_off = false
   start = false
end procedure

procedure update_fan_left ( byte in dutycycle ) is
   f877_ccpr1l = dutycycle	 	
end procedure

...
 if pushb_down then
        if fan_on_left then
           stop_fan_left ( fan_speed_left, fan_on_left, fan_starting_left )
        else
           start_fan_left ( fan_speed_left, fan_on_left, fan_starting_left )
           vtmr1_go = true
        end if
        if fan_on_right then
           stop_fan_right ( fan_speed_right, fan_on_right, fan_starting_right )
        else
           start_fan_right ( fan_speed_right, fan_on_right, fan_starting_right )
           vtmr2_go = true
        end if
     end if
     if pushb_set then
        fan_speed_left = fan_speed_left - 5
        update_fan_left ( fan_speed_left )
        fan_speed_right = fan_speed_right - 5
        update_fan_right ( fan_speed_right )
     end if
     if pushb_8 then
        fan_speed_left = fan_speed_left + 5
        update_fan_left ( fan_speed_left )
        fan_speed_right = fan_speed_right + 5
        update_fan_right ( fan_speed_right )
     end if
   end if
...

	LIST P=PIC16F628A, F=INHX8M
	__CONFIG _CP_OFF & _WDT_OFF & _HS_OSC & _LVP_OFF 

	include "p16f628A.inc"
	include "../inc/macros.inc"

;*****************************************************************************
; Equates, I/O, vars
;*****************************************************************************
RESET_V		EQU	0x0000		; Address of RESET Vector
ISR_V		EQU	0x0004		; Address of Interrupt Vector
OSC_FREQ	EQU	.20000000	; Oscillator Frequency is 20 MHz

;*****************************************************************************
; Program start
;*****************************************************************************
	ORG	RESET_V			; RESET vector location
RESET		goto	START

;*****************************************************************************
; This is the Periperal Interrupt routine. Should NOT get here
;*****************************************************************************
	ORG	ISR_V			; Interrupt vector location
INTERRUPT	GOTO    INTERRUPT	; Hang processor

;*****************************************************************************
; Initialize processor registers
;*****************************************************************************
START					; POWER_ON Reset (Beginning of program)
		CLRF	STATUS		; Do initialization, Select bank 0
		CLRF	INTCON		; Clear int-flags, Disable interrupts
		CLRF	PCLATH		; Keep in lower 2KByte

		CLRF	PORTA		; ALL PORT output should output Low.
		CLRF	PORTB

		BANK1
		MOVLW	0x07
		movwf	CMCON		; Port A is digital
		
		movlw	0xFF
		movwf	TRISA		; Port a All input
		MOVLW	b'11110111'	; RB3 (PWM) is output
		MOVWF	TRISB
		BSF	OPTION_REG, NOT_RBPU
					; Disable PORTB pull-ups
		BANK0

		CLRF	T2CON		; Stop Timer2, Prescaler = 1:1, Postscaler = 1:1
		CLRF	TMR2		; Clear Timer2 register
		BANK1
		movlw	.131		; Closest match to 26.3 usec
		movwf	PR2
		BANK0
		movlw	.61		; plm 50 % (132/61)
		movwf	CCPR1L
		movlw	b'00001100'	; Enable PWM mode, lsb's are 0
		movwf	CCP1CON
		bsf	T2CON,TMR2ON

		goto	$

		END

;BANK0
		BCF		STATUS,RP1
		BCF		STATUS,RP0

;BANK1
		BCF		STATUS,RP1
		BSF		STATUS,RP0

;; 013 :    f628_pr2 = 100 -- Tmr2 period reg: PWM period = (PR2+1).4.Tosc.(Tmr2_prescale)
  movlw   H'64'
  movwf   H'92'

-- f628_pr2 = 100 -- Tmr2 period reg: PWM period = (PR2+1).4.Tosc.(Tmr2_prescale)
   -- assembler workaround to tackle bankselect problem JAL
   assembler
      BCF		0x03,6
	  BSF		0x03,5
	  movlw	0x81		; 1 / 26.0 usec =38,461kHz
	  movwf	0x92
	  BCF		0x03,6
	  BCF		0x03,5
   end assembler
   f628_ccpr1l = 65