Thank you very much for your answer!

Of course I tried HPWM and I use 30 Projects Using PIC BASIC and PIC BASIC PRO as my Bible in programming, but it cannot give such low frequency as 85 Hz.

Apologies again for posting in thread with other topic, and I know that is annoying to make first post with question… I searched the entire web for tips for that for a long time – and recently found DT SPWM (many thanks for that) where frequencies below 255 Hz are possible. I just didn’t find someone made it with 12F683…
Anyway probably I will find time this weekend to try the code in this thread without changes in PWM, something like that:

Code:
DEFINE OSC 8

SPWMpin var GPIO.5 ' Output Pin for SSPWM
INCLUDE "SSPWM.inc" ' include the SSPWM module

;----[Constants]------------------------------------------
;HPWMfreq CON 20000
Freq = 85 ' Set Frequency of SSPWM (word)

;----[Variables]------------------------------------------
;HPWMduty VAR BYTE
;LastHPWMduty VAR BYTE
SSPWMduty VAR BYTE

;----[Initialize]-----------------------------------------
OSCCON = %01110000 ' 8Mhz
;ANSEL = %000011 ' AN0 and AN1 ANALOG
DutyCycle = 10 ' Set Duty Cycle of SSPWM
gosub StartSPWM ' Start SSPWM @ Freq/DutyCycle
;HPWM 1, 127, HPWMfreq ' Start 20Khz PWM @ 50%

;----[Main Program Loop]---------------------------------
Main:
;ADCIN 0, HPWMduty
;ADCIN 1, SSPWMduty

;IF HPWMDuty != LastHPWMduty THEN
;LastHPWMduty = HPWMDuty
;HPWM 1, HPWMDuty, HPWMfreq
; ENDIF


;DutyCycle = SSPWMduty*80/256+10 ' scale SSPWM dutycycle

DutyCycle = 95        ' set 95% nominal SSPWM dutycycle
gosub SetSPWM       ' Change SSPWM DutyCycle
GOTO Main
Maybe after all I will not need changes in ASM.