I ended up doing just that.

What I was looking for was something on the lines of:

----------------------------------
(make sure to TRIS port C,2 as an output)
;------------------------------ SETUP PWM --------------------

	MOVLW	B'11111111'		;SET PERIOD OF PWM
	MOVWF	PR2

	MOVLW	B'11111111'		;SET DUTY CYCLE (127 DEFAULT)
	MOVWF	CCPR1L

	MOVLW	B'00001111'		;SET OTHER CONFIG OF PWM
	MOVWF	CCP1CON

	MOVLW	B'00000100'		
	MOVWF	T2CON			;WRITE TO T2CON
----------------------------------

Yes, I know my 'default' isn't the same as this setting. While my 
default dim setting is 127, I started at 255 to start the backlight off 
then 'ramp it up' while the boot sequence is underway. Yes, I like 
little tricks like that. :-)

But, my backlight dim function is working perfect now.

I did take a shortcut which I will detail in my next email (provided you 
didn't see it above)

Joe M.


Jan-Erik Soderholm wrote:
> MCH wrote:
>> Maybe I'm getting too specific here. Let's make the net larger.
>>
>> Does anyone have an example of "working" ASM code that will configure 
>> and output PWM signals?
>>
> 
> Yes, the datasheet for the specific part. There usualy is a
> 1-2-3 guide on howe to configure the PWM module. You *are*
> talkig about the *hardware* PWM module, right ?
> 
> 
>> All I can find on the net is BASIC or C language.
>>
> 
> Since it's mainly a questions about setting up a few registers
> correctly, it would/should be easy to do the same thing as the
> BASIC or C examples do, but in ASM instead.
> 
>> I found one great tutorial site that says it has a section on PWM, but 
>> "PWM" is not mentioned once in their tutorial. :-\
>>
>> I also tried looking for app notes on the Microchip website. So, if 
>> anyone knows of a URL for that, it would greatly help as well.
>>
>> Again, just looking for a 'how to' with code examples of ASM code for 
>> the PWM output. It doesn't matter what is being controlled with the
>> output.
>>
>> I'm using an 18F4520,
> 
> OK, then. Chapter 15.4.4 "SETUP FOR PWM OPERATION" on page 145.
> It's 5 steps, 1 to 5. It's not actual code, but it says which
> register to set to what. If you can't translate that into ASM,
> well, then you have other issues to fix first.
> 
>> but any ASM code would be appreciated, as I'm sure I could translate it.
>>
>>
> 
> If you want ASM code, why "translate" ASM code that you get ?
> 
> 
>> Thanks, Joe M.
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist