ARM ARM926EJ-S User's Guide download pdf (Page 329)

CLCD Display and Adaptor Board

C.3 Touchscreen controller interface

The touchscreen interface is designed to connect to a four-wire resistive touchscreen. It

is driven by the TouchScreen controller TSC2200 and described in:

• Touchscreen interface architecture

• Touchscreen controller programmer’s interface on page C-13.

The

Selftest

program supplied on the CD demonstrates how to communicate with the

touchscreen controller. The program uses the interface code to plot the touchscreen X

and Y coordinates on the LCD or VGA screen.

Connectors J8 and J10 are used for the standard touchscreens provided with the CLCD

assembly. Prototyping connector J3 enables the use of other resistive touchscreens, see

Touchscreen prototyping connector on page C-17.

C.3.1 Touchscreen interface architecture

Figure C-7 on page C-12 shows the touchscreen interface. Table C-3 lists the

touchscreen control signals. The signals to the touchscreen are routed to connector J13.

Table C-3 Touchscreen host interface signal assignment

Signal name Description

TSMOSI Serial data input to controller

TS_nSS Chip select

TSSCLK Clock input

TSMISO Data output

TSnDAV Data available

TSnPENIRQ Pen down interrupt

TSnKPADIRQ Keypad interrupt

VBAT[2:1] and

AUX[2:1]

External voltage to analog to digital converter in touchscreen

controller. These are reserved for expansion for external devices

connected to the AD and keypad connector J13.

R[4:1] and C[4:1] Row and column scan signals for a keyboard. The expansion

board switches S3 to S8 currently use eight positions on the

scan matrix, but additional switches can be fitted using the AD

and keypad connector J13.

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ARM ARM926EJ-S User's Guide Page 329