210-210

The 210-210 is a VmodTFT board that allows to connect an LCD touch screen to any Diligent FPGA system board with a VHDCI connector. It acts as both an input and output device. The two plate four wire touch screen uses four analog lines connecting the opposite sides of the X and Y plates. A touch controller gives the touch screen an FPGA interface. The controller can both drive and sample the touch screen using a digital serial interface. The LCD is driven using a digital parallel interface. The VmodTFT uses an AD7873 touch controller to provide an interface for the analog touch screen to the FPGA. The controller supplies current to the touch screen and measures the voltage drop using an internal 12bit analog to digital converter. The digitized voltage values are read back by the FPGA so the touch coordinates can be determined. The VmodTFT is only compatible with system boards using 3.3V level signalling.