Quote Originally Posted by mister_e View Post
move res=24 before your repeatit label may help

Maybe not a bad idea to set the clock LOW at the top of your code.
Good catch. But even with the res=24 inside the loop, I'm still reading 100k across the wipers and the A terminals, and low resistance across the wipers and the B terminals. I slowed down the clock with a "define shift_pauseus 100", took the res=24 outside the loop, but still can't see any changes in resistance. Here's my adjusted code:

--------------------
cmcon=7
define osc 8
define shift_pauseus 100

res var byte

CS var porta.2 'CS
CLK var porta.3 'CLK
SI var porta.4 'SI
LED var porta.1 'LED

high CS
high LED
pause 500
low LED
pause 500
high LED

res=24

repeatit:
low CS
shiftout SI,CLK,1,[%00000000\8,res\8]
high CS
pause 10
low CS
shiftout SI,CLK,1,[%00010000\8,res\8]
high CS
pause 500
res=res+32
goto repeatit

end
--------------------
I also have 10k resistors between the MCP4261 pins and the 16F628A pins, but that shouldn't affect anything.

WP and SHDN can be left floating, right? Am I correctly formatting the command byte? Aren't the memory locations %0000 and %0001 the correct ones to address?

Thanks for the help!
Dave