Document No. DER-S0187A
3
Rev.2.0 ©2021 DMC Co., Ltd.
TSC-55/U-L User
’s Guide
1.3. Peripheral Composition Overview
5 wire resistive touch screen is operated by resistance sensitive system between two layers such as film or
glass. Two pieces of transparent materials with conductive coating are placed in the same direction as
two electrodes face each other. The 5 wire touch screen is activated when these transparent conductive
layers are pressed to contact each other with a finger or a pen. The one of these conductive layers func-
tions as an X/Y-coordinates electric circuits and the other as a detection circuits.
To measure the X-coordinates, TSC-55/U-L makes two corners Vcc among four corners. And makes others
GND. When the touch screen is pressed under this environment the voltage of the X-coordinates resistance
is detected by the detection layer (A_in) at the input point (x1), where the X-Y coordinate resistance layers
make contact. The detected voltage in supply side is higher than the GND side, which means
‘A_in’=Vcc
at the point
‘E’ and ‘A_in’=0(*1) at the point ‘A’. TSC-55/U-L calculates coordinates data starting from A/D
conversion of the
‘A_in’ voltage. The Y-coordinates is measured in the same way. By repeating this
process alternately, coordinate value at the input point is determined.
(*1) Excluding the loss in the controller circuits and touch screen. Actual detected voltage should be lower
than
‘Vcc - GND’ because of loss happened in the circuitry.
xl
A_in
Output Data
A
0V
0000h (Min.)
B
1.25V
00FFh
C
2.5V
01FFh
D
3.75V
02FFh
E
5V
03FFh (Max.)
Vcc
= 5.0V
T
o
u
c
h
5V
E
D
C
B
A
(Drive layer)
E
(Detection layer)
A_in
A_in
(TSC-50/IC)
(TSC-55/U-L)
USB
To host
xl
Detection layer
Touch
(Touch Screen)
Drive layer
E
D
C
B
A
Vcc
