How are you implementing the RS485?
How are you implementing the PWM?

I would recommend using the hardware PWM if you are not already. It
shouldn't react at all to any other action in the  PIC. Except messing with
the TIMER associated with the PWM.

If you use the hardware serial port (with a RS232-to-RS485 converter) then
it should not affect the PWM.


Best regards,
Fred


-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of John Ward
Sent: Sunday, June 06, 2004 1:13 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] USART RX interrupts


I have embarked on a similar exercise with the pic16f876.
I however am not doing the serial to serial thing between pics.. but from
a PC to pic via rs485 at about 200 odd Kbit.

My problem is that when the serial port gets data, it messes up the PWM
function ( software, runs on timer2) and makes the PWM vary the brightness
slightly. Not alot, but enought to make it flicker slightly

Anyone have a few wise words about this ?

Regards
John

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.