Capacitive Touch Screen Interface

Venkat Ramanan

Is it possible to connect a capacitive touchscreen with the AM335x controller directly. I know it supports the resisitive touch screen.

But what it would it take to interface a capacitive touchscreen with the controller?

over 12 years ago

0 Venkat Ramanan over 12 years ago

Intellectual 270 points

If its not possible to interface the capacitive touchscreen directly with the controller, can someone suggest an external surface capacitance based touchscreen controller to interface with the Starter Kit.

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Venkat,

You will need and external controller for capacitive touchscreen. Most of these communicate through I2C.

0 Biser Gatchev-XID over 12 years ago in reply to Biser Gatchev-XID

TI__Guru**** 393215 points

The AM335X Starter Kit has interface for a display with capacitive touchscreen. Here is a link to the display datasheet: http://www.newhavendisplay.com/specs/NHD-4.3-480272MF-ATXI-CTP.pdf

0 Venkat Ramanan over 12 years ago in reply to Biser Gatchev-XID

Intellectual 270 points

But as per the Hardware User Guide, a resistive touchscreen is being used in the Starter Kit

http://processors.wiki.ti.com/index.php/AM335xStarterKitHardwareUsersGuide#LCD

0 Biser Gatchev-XID over 12 years ago in reply to Venkat Ramanan

TI__Guru**** 393215 points

If you check the SK schematics, page 9, a capacitive touchscreen can be optionally attached.

0 Venkat Ramanan over 12 years ago in reply to Biser Gatchev-XID

Intellectual 270 points

Yeah right, but it is though the I2C interface. My question was, can we interface a capacitive touchscreen directly to the controllers's ADC pin, the way we do for resistive touchscreens.

0 Biser Gatchev-XID over 12 years ago in reply to Venkat Ramanan

TI__Guru**** 393215 points

No, this isn't possible.

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Capacitive Touch Screen Interface