12F683 2 x PWM Outputs

[deodeo]

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:

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.

[Hebemabo]

Hi,
I copied the program into Microcode Studio and when I compile it I get
the following errors:

ERROR: Variable wsave3 position request 416 beyond RAM_END 191.
ERROR: Variable wsave2 position request 288 beyond RAM_END 191.

I Googled the errors and searched the forum but cant find an answer.

Please help.
Hebemabo

[HenrikOlsson]

Which program, exactly are you talking about? There are several ones in this thread - is it one of them?
And what PIC are you aiming to use and have you selected that particular one in MicrocodeStudio?

/Henrik.

[Hebemabo]

Hello Henrik , its the code just before my reply. The one by deodeo.

I am programming a 12F683 using PBPro , Microcode Studio , MPASM and Pickit2.
I have selected 12F683 in MicrocodeStudio.

[mark_s]

Just like DT's interrupt routines, you some times need to comment out a few lines in the include file

Look inside "SSPWM.inc"

' --- IF any of these three lines cause an error ??  Simply Comment them out to fix the problem ----
wsave1      var byte    $A0     SYSTEM          ' location for W if in bank1
wsave2      var byte    $120    SYSTEM          ' location for W if in bank2
wsave3      var byte    $1A0    SYSTEM          ' location for W if in bank3
' ------------------------------------------------------------------------------

[Hebemabo]

Thank you very much Mark.