The original delay loop is for a 4MHz oscillator. For creating timing loops,
I use a neat little program called picloops (just google for it).

The erratic operation sounds like a mclr issue. 

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Rikard Bosnjakovic
Sent: Thursday, March 15, 2007 9:32 AM
To: Microcontroller discussion list - Public.
Subject: [PIC] First shot errors

So, finally I was able to use a programmer and a chip (16F628a to be exact).
Feeling the rush of excite, I immediately hacked together a "running
light"-test in MPLAB, just for the sake of trying the microcontroller out.
It worked the first time, I was amazed!

But, since this opposed to using MPLAB is reality, the happiness was not for
long; because there were some errors. The lights (LEDs) were running, sure,
but the supposed delay of 5 seconds between each light is wrong; the lights
are in a sort of rush hour and then stops. I don't know if this occurs
codewise or breadboard-wise, but probably the latter, because if i touch the
board or some pins, the lights start again. Sometimes they run, sometimes
only one is lit, etc. Some oscillation perhaps? Nothing except the PIC and 4
LEDs are connected on the board.

I also thought it might had to do with the lack of crystal (I used the
internal oscillator), but alas; adding a 14MHz-crystal and proper caps did
not solve the problem. The lights surely runs even faster, but the problem
still occurs.

I'm attaching my code that I used for testing, feel free to take a peek and
berate me to better knowledge.


--
- Rikard.

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