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List:       linux-arm-kernel
Subject:    Re: Touch driver operational characteristics
From:       Russell King - ARM Linux <linux () arm ! linux ! org ! uk>
Date:       2002-01-30 10:03:57
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On Tue, Jan 29, 2002 at 01:35:02PM -0500, Jeff Sutherland wrote:
> Synchronous mode:
> X		Y
> 1.154964	1.555677
> 3.651898	1.456615
> 3.836583	6.353472
> 1.540299	4.258906
> 
> Asynchronous mode:
> X		Y
> 1.107724	0.617353
> 1.568621	0.780368
> 1.339944	0.929525
> 2.675366	1.412046

Something I've changed in the 2.5 driver a while ago (and hasn't yet made
it back into the 2.4 stuff) is the timing between switching the plates and
taking a sample.

With async mode, its far better to take two readings, and discard the
first since there are filters between the touchscreen and the UCB1x00
inputs.  Maybe a schedule call would be better, especially as you don't
really want to wait two ADC SYNC periods per sample.

Note: 2.4 stuff does tend to be older than 2.5, so please always take a
look at the 2.5 stuff first - 2.4 stuff isn't development anymore, so its
rather slower moving than 2.5.

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