Hi Team,
A customer use TSC2004 in touch panel, want use hand write function. But when low pressure writing, the position would jump, as the below picture(that sharp curve)
[PIC show is not ok. attached as 1.bmp]
From the oscilloscope, in some point, when pressure low, the measured voltage would drop in the middle, such as below point A(X+ waveform)
[PIC show is not ok. attached as 2.bmp]
below is Y+ waveform
[PIC show is not ok. attached as 3.bmp]
these voltage change during ADC sampling would make output point error. From the waveform, it seems some discharge or charge happens in the middle of sampling, will the MUX inside would do something strange? Do you have any suggestion about the root reason or how to bypass this issue? Thanks.
attached more waveform. also in some case, when press too low, the sampling senquence would get wrong, such as scope_10.bmp.
Best Regards
Dylan
http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/750/4375.TSC2004-low-pressure-touch.7z
http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/750/7183.PICs.7z
