Display NHVN surprising results

I hooked up my new Newhaven 4.3" cap touch display to the GHI NHVN tonight. Then after a LOT of searching I found out how to use GHI’s cap touch driver and how to make the display work with the Spider2. I was VERY surprised to see that I’m getting touchdown events every few hundred MS from the display (display raising the interrupt line and the GHI cap touch driver responding.)

I have the GHI cap touch driver instantiated thusly:

P0_12 is Pin 3 on the I socket which is what the driver docs say is the correct pin. Either I am tired and set the wrong pin or these displays need 'configured' in some other way. I noticed something about a 'touch threshold' in the Newhaven docs?

Any thoughts?

Hi Jeff,

How is the display mounted?

I’ve not noticed any delays with the touch but then I am using a different driver.

Could you try this one?


Is that with or without touching? Those displays continually raise events while touched even without any movement, I have code that does a good job filtering that

The interrupt is raised without touching the display. It is just sitting on my desk. I saw you filter out repeated touch events in the same location but first I would like to figure out how to prevent the display from generating the spurious events.

OK, I am a moron! :-[

After looking over the Newhaven datasheets and touch controller registers it finally occurred to me that POWER might be an issue. I was running on USB power, plugged into a powered hub, with a short cable but what the heck, it was worth a try.

I plugged a 6V wall-wart in and rebooted and now it works perfectly. I’ll let it run for a few hours and then do some probing with and without the wall-wart to see, specifically, what the problem is with power (low voltage, noise, etc.)