MK712 Datasheet, PDF (1/16 Pages) Integrated Circuit Systems – Touch Screen Controller

I CR O C LOC K
MK712
Touch Screen Controller
Description
Features
The MK712 Touch Screen Controller IC provides
all the screen drive, A to D converter and control
circuits to easily interface to 4-wire analog resistive
touch screens.
The IC continually monitors the screen waiting
for a touch. In this mode, the supply current is
typically 0.5µA. When the screen is touched, the
IC performs analog to digital conversions to
determine the location of the touch, stores the X
and Y locations in the registers, and issues an
interrupt. This process is repeated up to 197 times
per second until no further screen touches are
detected, at which time the low current mode is
resumed.
Block Diagram
8
D0-D7
3
A0-A2
CS
RD
WR
REGISTERS
STATUS LOW ⁰
STATUS HIGH ¹
X-LOW ²
X-HIGH ³
Y-LOW 4
Y-HIGH ⁵
CONTROL ⁶
RATE
7
CLKIN
(14.318 MHz)
INT
TOUCH
12 Bit A/D,
Screen Driver
and
Controller
• Fully integrated, lowest power solution
• Low standby current of 0.5µA (typical) at 5.0V
• Active current while converting less than 10 mA
• Resolves 350 dots/inch on 10.5” display
• Maximum speed of 197 points/second
• Ratiometric conversion may eliminate screen
calibration
• Automatically wakes up and goes back to standby
• 3.3V or 5V supply
• 12 bit A/D converter
• Simplifies the writing of software for touch screens
• Extended temperature range available
• Capacitors are the only external components
required
• Touch screen is directly driven - no external
transistors are required
• Programmable conversion rate
• A to D Converter is monotonic
• Parallel interface
• See the MK715 for a serial interface
Pin Assignment
NC 1
INT 2
TOUCH 3
VDD 4
VDD 5
XH 6
XL 7
YH ⁸
YL ⁹
GND ¹⁰
XH
GND ¹¹
XL
WR 12
YH
RD ¹³
YL
CS 14
28 D0
27 _D1
26 _D2
25 _D3
24 _D4
23 D5
22 VDD
21 _GND
20 _D6
19 _D7
18 _CLKIN
17 _A0
16 _A1
15 _A2
MDS 712 I
1
Revision 100899 Printed 11/16/00
Integrated Circuit Systems, Inc.•525 Race St.•San Jose•CA•95126•[phone]tel•www.icst.com