4-wire resistive touch interface

This kind of touch screen interface connects to the touch screen by four wires in two pairs: (TSPX and TSMX), (TSPY and TSMY). A 4-wire resistive touch screen consists of two conductive film layers which are laminated to a solid base material or directly to the TFT screen. Each layer has two electrodes. One layer has an electrode on the left and one on the right edge. The other layer has one on the top and one on the bottom edge. When connecting the touch screen it is important to connect one signal pair to one layer.

For example:

• TSPX to the left electrode and TSMX to the right electrode
• TSPY to the upper electrode and TSMY to the lower electrode

As long as each wire pair is connected to one layer, every combination will work.

After proper connection the touch screen needs to be calibrated.

For in-depth information on how the 4-wire touch interface is implemented on the colibri module see the UCB1400 or WM9715 datasheet.