Re: 12F675 Startup Problems

Started by starutopy December 15, 2007
you may try to bypass VDD & VSS by an 100nF capacitor as close as
possible to pin 1 & 8. Then don't connect directly pin 1 to 4, but put
a resistor 100K from pin 1(VDD) to pin 4 (MCLR) and a capacitor 100nF
from pin 4 to pin 8 (VSS).
Best regards

--- In p..., "kg4pid" wrote:
> I'm using a serial routine on a 12F675 and started by sending out the
> word "HELLO" over and over. Funny thing is while it's powered on I get
> nothing out, but the instant I remove power it sends out 10 or 11
> characters. The filter cap is powering it for that fraction of a
> second. The circuit is being powered by a 9V battery with a 78L05 to
> regulate it at 5V. My meter reads 4.99v at the pic chip. A logic probe
> connected to the output blinks the whole time it is powered up which
> should mean that its sending something. I had to include this bit of
> code at the very beginning before I got anything at all.
> call 0x3FF ; Retrieve Factory Calibration
> movwf OSCCAL
> Anyone have any ideas as to what might cause a problem like this?
> Thanks, Max