The Studying And Implementation Of Touch Screen In The Embedded Military PDA System

This thesis mainly focuses on studying, design and implementation of a Touch Screen Module of military PDA system based PXA255. The dominated controller of it is TSC2301 which is manufactured by TI Corporation. It contains a complete 12-bit A/D resistive touch screen converter (ADC) including drivers, touch pressure measurement capability, keypad controller, and 8-bit D/A converter (DAC) out-put for LCD contrast control. A register-based architecture eases integration with microprocessor-based systems through a standard SPI bus. All peripheral functions are controlled through the registers and onboard state machines.The module of PDA system selects a resistive 4-wire touch screen. When the touch panel is pressed or touched, there are two signals-X and Y, must be generated. They are inputted into TSC2301 and are converted to digital signal, then are transmitted to PXA255. After this process the touch screen function can be implemented.All peripheral functions are controlled through writing command words into TSC2301 internal register. Through studying register, AD/DA, data format, communication protocol of TSC2301, the work module of TSC2301 is introduced. In addition, the design of module circuit, register configuration, driver etc. in the system are discussed. And touch screen function is reliable after system debugging.