Motorola M68EZ328ADS - Manual (Page 25)

Hardware Description and Board Operation
MOTOROLA M68EZ328ADS v2.0 USER’S MANUAL 3-24
For full description of the LCD signals, please refer to the MC68EZ328 User’s Manual.
3.9.2 Touch Panel Interface
The M68EZ328ADS board is equipped with Burr-Brown Touch Panel Controller ADS7843.
Figure 3-9 shows the interface of Touch Panel Controller. Totally one I/O signal, one inter-
rupt capable I/O signal and one set of SPIM signals from MC68EZ328 are used to imple-
ment the touch panel circuitry. All of these signals can be shared for other devices when
touch panel interface controller is being disabled. The on-board touch panel controller can
be disabled by turning both DIP switches S1-4, S1-5 off.
The ADS7843 is a 12-bit sampling analog-to-digital converter (ADC) with a synchronous
serial interface and low on-resistance switches for touch screens. The ADS7843 communi-
cates with MC68EZ328 through SPI (Serial Peripheral Interface). In this case, ADS7843 is
a slave, and MC68EZ328 is a master. For the detailed operation of ADS7843, please refer
to its datasheet. The datasheet is available at the following web site.
http://www.burr-brown.com
For more details on the operation of resistive touch panel, please refer to Appendix B .
Table 3-6. Signal Assignment for Touch Panel Controller
Signals Function
SPMRXD, SPMTXD, SPMCLK
This set of serial port interface signals performs data transfer with
ADS7843. For detailed operation on the SPI port, please refer to the
MC68EZ328 User’s Manual.
~IRQ5 This signal is a MC68EZ328 interrupt capable I/O pin.
PB6
This MC68EZ328 general I/O signal is used to select the ADS7843 on data
transfer.
ADS7843
CS
PENIRQ
IRQ5
PB6
SPMCLK
SPMTXD
SPMRXD
DCLK
DIN
DOUT
Touch Panel TOP
RIGHT LEFT
BOTTOM
MC68EZ328
S1-5
S1-4
VCC
Figure 3-9. Touch Panel Controller Interface
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
For More Information On This Product,
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ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005
ARCHIVED BY FREESCALE SEMICONDUCT
OR,
INC.
2005