GPIO not working

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v8dave
Posts: 333
Joined: Thu Dec 31, 2009 8:31 pm

GPIO not working

Post by v8dave »

Hi all,

I have a touch screen driver IC connected to the SPI bus with the PENIRQ output of the IC connected to IRQ3 input on the MOD5234 I am using.

I have used the following to setup the IO pin as a GPIO input as I only want polling at the moment. After I do this, the input never goes low and there is a waveform present when checked with a scope. I don't init the IC at this time as the power on default is to generate a LOW on PENIRQ output when the touchscreen is touched. If I reset the Netburner and don't yet run the code, I can see PENIRQ trying to go low. It is sitting at 3.36V and goes to 3.20V when I touch the screen.

J2[45].function(PINJ2_45_GPIO); // Pen touch input

I then read the input using the following

State = J2[45];

I just never get the IO line going low.

What am I missing?

Cheers,
Dave...
v8dave
Posts: 333
Joined: Thu Dec 31, 2009 8:31 pm

Re: GPIO not working

Post by v8dave »

Sorted. It was actually a short in the Chip Select and SPI clock lines on the touch driver IC that was causing the strange issue.

Damn these small TSSOP IC's !! :)

Dave...
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