Datasheet

8
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TSC2000
SBAS257
FIGURE 1. Typical Circuit Configuration.
OVERVIEW
The TSC2000 is an analog interface circuit for human inter-
face devices. A register-based architecture eases integration
with microprocessor-based systems through a standard SPI
bus. All peripheral functions are controlled through the reg-
isters and onboard state machines.
The TSC2000 consists of the following blocks (refer to the
block diagram on the front page):
• Touch Screen Interface
• Battery Monitors
• Auxiliary Inputs
• Temperature Monitor
• Current Output D/A Converter
Communication to the TSC2000 is via a standard SPI serial
interface. This interface requires that the Slave Select signal be
driven LOW to communicate with the TSC2000. Data is then
shifted into or out of the TSC2000 under control of the host
microprocessor, which also provides the serial data clock.
Control of the TSC2000 and its functions is accomplished by
writing to different registers in the TSC2000. A simple com-
mand protocol is used to address the 16-bit registers. Reg-
isters control the operation of the A/D converter and D/A
converter.
The result of measurements made will be placed in the
TSC2000’s memory map and may be read by the host at any
time. Three signals are available from the TSC2000 to indicate
that data is available for the host to read. The
DAV output
indicates that an A/D conversion has completed and that data
is available. The
PENIRQ output indicates that a touch has
been detected on the touch screen. A typical application of the
TSC2000 is shown in Figure 1.
+
Auxiliary Input
Auxiliary Input
Pen Interrupt Request
Serial Data Out
Data Available
Serial Data In
Slave Select
Serial Clock
1µF
to
10µF
(Optional)
+2.7V to +3.3V
Touch
Screen
0.1µF
+V
DD
X+
Y+
X–
Y–
GND
V
BAT1
V
BAT2
V
REF
NC
AUX1
AUX2
ARNG
A
OUT
PENIRQ
MISO
DAV
MOSI
SS
SCLK
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
TSC2000
+
1µF
to
10µF
(Optional)
0.1µF
Main
Battery
Secondary
Battery
LCD Contrast
Voltage
Regulator
RRNG