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For full description of the LCD signals, please refer to the MC68EZ328 User's Manual.
3.9.2 Touch Panel Interface
ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005
MC68EZ328
PB6
IRQ5
SPMCLK
SPMTXD
SPMRXD
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.
Table 3-6. Signal Assignment for Touch Panel Controller
Signals
SPMRXD, SPMTXD, SPMCLK
~IRQ5
PB6
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.
For more details on the operation of resistive touch panel, please refer to Appendix B .
MOTOROLA
Freescale Semiconductor, Inc.
VCC
S1-5
S1-4
Figure 3-9. Touch Panel Controller Interface
This set of serial port interface signals performs data transfer with
ADS7843. For detailed operation on the SPI port, please refer to the
This signal is a MC68EZ328 interrupt capable I/O pin.
This MC68EZ328 general I/O signal is used to select the ADS7843 on data
http://www.burr-brown.com
M68EZ328ADS v2.0 USER'S MANUAL
For More Information On This Product,
Go to: www.freescale.com
Hardware Description and Board Operation
Touch Panel
ADS7843
CS
PENIRQ
DCLK
DIN
DOUT
Function
MC68EZ328 User's Manual.
transfer.
TOP
LEFT
RIGHT
BOTTOM
3-24
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