MCP41xxx Digital pot issue

[HenrikOlsson]

Hi,
With MODE 5 the clock should idle high and go low and return high for each bit of data.
You don't say which PIC this is but you have the Clock output on PortA where analog stuff is normally located. Check and double check that analog functions are turned OFF for the pins used as Clock and data.

/Henrik.

[jmgelba]

PIC 18F2550

There is data from each pin so the pins are correctly set to digital outputs. The clock does idle high and goes low for each bit. I'm stumped. I've followed code I've used before that has worked. No idea what is wrong this time.

[HenrikOlsson]

You have ADCON1 = %00000000 which for the 18F2550 means ALL analog inputs enables, that includes PortA.5 where you have your SDO pin - that doesn't look quite right to me. Then, looking at the datasheet for MCP41xxx it's pretty clear that it clocks the data in on the rising edge of the clock so you probably have the wrong polarity selected in the SHIFTOUT command.

/Henrik.

[jmgelba]

The mode is correct but I did miss the analog setting. Thank you.