Anno, Jeff wrote:
> Occasionally it appears that the chip has 'reset' because I get the
> "Power On" text appearing when I haven't unplugged it.  It would also
> stop reporting "Channel X" when I would send it "X".  I could wiggle
> and touch the cable and it would start working again after the power on
> message.
>
> I am powering it through a wall wart (8 V DC) and then across a 5V
> regulator (also tried a linear DC Power Supply).  I have tried two
> different chips to ensure that it wasn't an individual chip problem.
> The chip had given the flaky results when it was on my bread board, so
> I made a circuit board and still had the same flaky communication.  I
> have Pin 5 going to ground, Pins 2 & 3 going to the RS232 chip (tried
> Maxim 232CPE and Sipex 232ACP). I have tried connecting the shield to
> ground and got a reset each time.  I have the five 1uf electrolytic
> caps for the rs232 chips with the right polarity (triple checked).
>
> I even connected pins 1, 4, & 6 together as well as 7 & 8. Nothing I
> have tried helps.  The cable is the same cable that I program the chip
> with, so I don't see any issues with it either.  Any Suggestions????

It probably has nothing to do with the RS-232 part.  Do you have a 100nF
ceramic bypass cap accross the power as close to the PIC pins as possible?
What is connected to MCLR?  What is connected to PGM?  Is the watchdog
enabled in the code?  Is low voltage programming enabled?  What is the
lowest voltage the "8V DC" wall wart produces over a power cycle?  Is the 5V
output of the regulator really 5V and steady?  Is it a 7805 regulator?


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