T6963 questions

[Brady]

I recently purchased a custom CFAG from CrystalFontz, with the T6963 controller. I have run into one problem, and I'm not sure what the root of the problem may be.

We initialize all of our home addresses, modes, etc, but we still don't see anything on the screen, even if we write something to it.

We think it may be one of two things, or both:

#1)
We purchased this LCD no potentiometer on it, so we had Vee and Vo sitting as open. We figured we'd need these for contrast adjusement, so we purchased a 10k pot, hooked the wiper into Vo, and hooked the other two pins on the pot between Vee and 5V (Vee is called '-20 V, Negative Voltage, and Vo is called 'Power Supply For LCD Driver', with no value given). Is it possible that the contrast is still too dim and we're just not seeing the data?

#2)
The microcontroller we're using operates at 40Mhz. We're sure we've accounted for the delays with rise and fall time of certain bits (C/D, RD, etc), but we're still stuck.

Any suggestions anyone?

Thanks,
Shawn

Crystalfontz LCD Blog

Looking for additional LCD resources? Check out our LCD blog for the latest developments in LCD technology.

 

[cosmicvoid]

1. If your LCD voltage (Vo) is hooked up correctly, it seems like you'd be able to make the screen go from clear to black with sufficiently negative voltage, without regard to any data being displayed. Assuming that the initialization is good. You could try posting your init sequence.

2. A good troubleshooting technique is to put delays of several milliseconds between all transitions of all of the control signals. This will eliminate any timing problems. I'm not sure what you mean by "the delays with rise and fall time of certain bits". The rise and fall times should be only a few 100 nS at most.

I have not yet actually looked at the data sheet for that controller... these are just generic suggestions.