Datasheet

Touch panel is a glass panel whose surface is covered
with two layers of resistive material. When the screen
is pressed, the outer layer is pushed onto the inner layer
and appropriate controllers can measure that pressure
and pinpoint its location. This is how touch panels can be
used as an input devices. EasyMx PRO
™
v7 for STM32 is
equipped with touch panel controller and connector for
4-wire resistive touch panels. It can very accurately
register pressure at a specic point, representing the
touch coordinates in the form of analog voltages, which
can then be easily converted to X and Y values. Touch
panel comes as a part of TFT 320x240 display.
Touch Panel
controller
Figure 17-2:
Turn on switches
SW11.5, SW11.6,
SW11. 7 and
SW11. 8 to enable
Touch panel
controller
Touch panel is enabled using SW11.5,
SW11.6, SW11.7 and SW11.8 switches.
They connect BOTTOM and LEFT lines of the
touch panel with PB0 and PB1 analog inputs,
and DRIVEA and DRIVEB with PB8 and PB9
digital outputs on microcontroller sockets.
Make sure to disconnect other peripherals, LEDs
and additional pull-up or pull-down resistors
from the interface lines so they do not interfere
with signal/data integrity.
Enabling Touch panel
multimedia
CN29
PMRD
PMWR
GND
VCC
NC
RS
NC
D1 D2 D3 D4 D5 D6 D7
CS
D0
RST
NC
+5V
BPWM
1 20
XR
YU
XL
YD
21 24
GLCD-TFT SOCKET
Q3
BC856
Q4
BC846
R61
10K
R59
1K
VREF
R65
10K
R63
4K7
VCC-3.3V
Q6
BC856
VREF
R67
10K
Q7
BC846
R71
10K
C35
10nF
R70
100K
Q8
BC846
R78
10K
C40
10nF
R77
100K
R75
4K7
VCC-3.3V
RIGHT
TOP
DRIVEA
DRIVEB
E14
10uF
VCC-3.3V
FP4
FERRITE
E15
10uF
VCC-1.8V VREF
LEFT
BOTTOM
PB8
PB9
1
2
3 4 5 6 7 8
O
N
SW11
DRIVEA
DRIVEB
LEFT
BOTTOMPB0
PB1
DATA BUS
RIGHT
TOP
LEFT
BOTTOM
Figure 17-1: Touch Panel controller
and connection schematic
page 31
EasyMx PRO
v7
NOTE:
VREF=1.8V