PIC PROBLEM

[Thomas Arrhenius]

I'm using a PIC16C54 to interface a PC with some solenoid valves. The
PC communicates with the PIC using a 2 wire serial link (using the PC
parallel port). Everything works fine, but when motors (having nothing
to do with the instrument in question) on the same AC circuit are
switched on and off the PIC seems to reset. If the PC to PIC
communications line is disconnected this doesn't happen. Any ideas about
how to prevent this?

[Tom Alldread]

TA>From: Thomas Arrhenius <Tom_Ar...@cytelcorp.com>
>Subject: PIC PROBLEM

TA>I'm using a PIC16C54 to interface a PC with some solenoid valves. The

Greetings Thomas:

You might consider employing an optical isolator in your 2 wire
data link and ensure there is no other direct connection between the PC
and the PIC. This approach should isolate any A/C power circuit
common mode transients from passing through the PIC circuit. If your
data link is bidirectional you would need to employ a pair of optical
isolators and you possibly may wish to consider setting up a 4 wire
connection between the PIC and the PC for bidirectional communications.

I hope this information is helpful and I wish you good luck but
with the usual disclaimer that I do not accept any responsibility
regarding any situations that could result from the use of this
information.

---
* QMPro 1.53 * Very Best Regards, tom.al...@minfox.com

[Soobong Choi]

I have smiliar problem of yours. Do you received any solution about
that problem. Please send me the information if any.

[William A Moyes]

Soobong Choi (sbc...@nuri.net) wrote:
: I have smiliar problem of yours. Do you received any solution about

: that problem. Please send me the information if any.

You are not alone. I was working with a 40x2 line LCD display.
The display was controlled by a PIC microcontroller (16C84). The PIC had
its MCLR tied directly to +5. I was powering it off my PC's powersupply
(thru the floppy drive power connector). When I connected an inverter to
+5 (to power the EL backlight) the PIC would reset and then come back
on-line. I know the PC's powersuppply provides more than enough current
to power the device. This might be a good question for Microchip.

-William Moyes
wmo...@cello.gina.calstate.edu

[Jonathan Dale Kirwan]

William A Moyes (wmo...@cello.gina.calstate.edu) wrote:

Has anyone observed MCLR at the time the PIC resets?

Jon