Touch screen question

What is the easiest/best way to drive a 4-wire resistive touch screen with the Beagleboard?

Thanks,

Bob Waddell

Display Technology Solutions LLC

28731 Dixboro Rd.

South Lyon, MI 48178

(248) 719-0105 Cell

(248) 437-4206 Office

dtslcd@gmail.com

Representative for:

American Industrial Systems Inc. (AIS) - Display systems integrator

Inteltronic Inc. - TFT and OLED manufacturer

RPM-Tronics - Monochrome LCD manufacturer, Standard and Custom

What is the easiest/best way to drive a 4-wire resistive touch screen with
the Beagleboard?

Take a look at the Palo43 LCD interface card from Gumstix
(www.gumstix.com). They publish schematics so you can see exactly
how they handle the touchscreen interface. Their Overo product is
quite similar to the Beagleboard so changes will be minimal.

Steve

What is the easiest/best way to drive a 4-wire resistive touch screen with the Beagleboard?

You need voltage translator like TXS0108 and then a ADS7846 touchscreen controller connected via SPI to the BeagleBoard. Digikey has a kit TSC2046EVM which you can connect to the BeagleBoard via a voltage translator.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-17516-ND

http://focus.ti.com/docs/prod/folders/print/txs0108e.html

Oh, and one more thing, you need a 3V3 LDO regulator to give you 3.3V from the BeagleBoard 5V pin on the Beagleboard J3 connector. Use this voltage to drive the TSC2046 and the high side of the voltage translator. The 1v8 for the low side of the voltage translator is connected to the 1v8 pin on the J3 connector.

Regard,

John

Thanks,

Bob Waddell

Display Technology Solutions LLC

28731 Dixboro Rd.

South Lyon, MI 48178

(248) 719-0105 Cell

(248) 437-4206 Office

dtslcd@gmail.com

Representative for:

American Industrial Systems Inc. (AIS) - Display systems integrator

Inteltronic Inc. - TFT and OLED manufacturer

RPM-Tronics - Monochrome LCD manufacturer, Standard and Custom

What is the easiest/best way to drive a 4-wire resistive touch screen with the Beagleboard?

You need voltage translator like TXS0108 and then a ADS7846 touchscreen controller

connected via SPI to the BeagleBoard. Digikey has a kit TSC2046EVM which you can

connect to the BeagleBoard via a voltage translator.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-17516-ND

http://focus.ti.com/docs/prod/folders/print/txs0108e.html

Oh, and one more thing, you need a 3V3 LDO regulator to give you 3.3V from the BeagleBoard

5V pin on the Beagleboard J3 connector. Use this voltage to drive the TSC2046 and the high

side of the voltage translator. The 1v8 for the low side of the voltage translator is connected

to the 1v8 pin on the J3 connector.

First of all – Sorry for this delayed reply. Just wanted to add, that you can get a newer version of the chip with 1.8V IO (TSC2046) and thereby avoid the TXS0108 level converter. This chip is actually the one used on the eval-kit referenced by John above…

Good luck

Søren