Halogen lights give off a load of uv - thats why they need a glass plate
over the bulb and you should be further than a metre away at all times.  It
could be erasing the chip.

Tim


At 10:02 09/07/97 -0400, you wrote:
>Here is my setup:
>
>PIC14000 acting as I2C master sending 5 bytes to a PIC16C63 acting as I2C
slave.
>PIC16C63 buffers the I2C data and sends it to a PC via RS-232.  I can look
on a
>scope and see the 5 I2C bytes followed by the 5 (plus checksum, total 6)
bytes
>on the RS232 line.
>
>One of the bytes from the PIC14000 indicates how many data bytes are in the
>message.  There is a three byte header and two data bytes for this test.
>I know the protocol of the I2C doesn't need a "number of bytes" parameter;
that
>info is used by the RS232 portion of the 16C63, so it has to stay.
>
>Everything works fine until I place my hand between my 100W halogen desk lamp
>and the PIC14000.  The PIC14000 still only sends 5 bytes but the PIC16C63
starts
>sending lots of data (lots and lots...).  Presumably the 14000 is telling the
> 16C63
>that there are more than 2 data bytes.  This is strange, but what is also
> stranger
>is that it only works with the light _on_.  When I block the light or turn it
> off the
>PIC losses its mind.  This doesn't bode well for a dark, windowless OTP
14000.
>BTW, the 16C63 doesn't have any problems (that I can detect).
>
>The first think I thought of is the internal 4Mhz clock of the 14000 is
> fluctuating
>enough that the I2C master clock and data timing are moving outside the
limits.
>That isn't happening.  I confirmed it on the scope.
>
>Any ideas?  Will the OTP parts exhibit the same behavior?
>
>-tim drury
>
>


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