SBC Axel SBC/Interfaces and Connectors/Touchscreen

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Version Issue Date Notes
1.0.0 Oct 2020 First DESK release

Touchscreen[edit | edit source]

Description[edit | edit source]

The 4-wire resistive touch controller signals are routed to J50, which is a 4 pin (1mm pitch vertical) ZIF connector for the 4-wires resistive controller.

The touch controller is a TI TSC2003 device, connected to the I²C2 bus (address 0x1001000b).

Touchscreen connector

Signals[edit | edit source]

The following table describes the interface signals:

Pin# SOM Pin# Pin name Pin function Pin Notes
1 - TSC_YP Touch controller Y+
2 - TSC_XP Touch controller X+
3 - TSC_YM Touch controller Y-
4 - TSC_XM Touch controller X-

Device mapping[edit | edit source]

The device is typically mapped to /dev/touchscreen0 device in Linux.

The touch controller is attached to the generic Linux input event interface (evdev).

Device usage[edit | edit source]

The simplest tools for touch screen management are the tslib library and ts_tools utilities. To calibrate the touch screen, the ts_calibrate command line tool is available. After calibration, the touch screen can be tested using the graphical ts_test utility or the ts_print command line tool.