>Dave,
>        This relates to a project I'm working on which uses a Dallas 1669
>non-volatile digital potentiometer and a PIC16C54A. Upon powerup I don't
>want any glitches getting to the 1669 and incrementing the wiper
>position (I want the output pin to be high). According to the 16C54A
>data sheet the PORTA and PORTB registers are undefined upon RESET and
>the TRIS is 11111111, all inputs so it appears to be OK if I have a
>pullup resistor on the I/O and set the I/O register bit to 1 before I
>set that pin as an output. Just double checking to see if there is a
>potential problem here. Thanks
>
>Dan Mulally
>dmulally@silver.sdsmt.edu

On a project where I used the DS1669, it was necessary to put a 0.1uf mono
bypass cap right on the socket. Otherwise, it would randomly switch from
dual-button mode to single-button mode. That resulted in wiper movement in
exactly the opposite from the desire direction 50% of the time.

Reg Neale