AD5206 Digital Potentiometer wiring

I'm having a few problems with an AD5206 10k digital potentiometer. All of the examples I've seen so far (including the one in the tutorials section here) show all of the potentiometer circuits wired. I only need 2 of the channels. Is there any problem with leaving the unused pins disconnected? Should I be thinking of running them to ground? (I do have Vss tied to ground.)

What I'm seeing is sporadic failure of an SPI write to set the resistance. I also see a moderate difference between output voltages for the same value. (For instance, my script sets a pot to 126 and there is a 5v input. Between tests I get between 2.38 v and 2.54 v. Input voltage is being supplied by the Arduino 5v output.)

Unused channels can just be ignored.

The failures and inconsistencies you are seeing may well be down to communication corruption. How do you have it wired up?

Try slowing the SPI communication down using SPI.setClockDivider(...)

setClockDivider may have helped. I'm not dropping commands now.

However, in the meantime I found that the chip I was using seems to have been damaged. My fault really. I was careless while connecting a battery. I swapped it for a new chip and everything is working well now.

In a bit I'll take out the setClockDivider command and will test whether I'm losing commands or not with the new chip.

Thanks for your help!