Altera tPad DE2-115 - 3.3 Using the 8 LCD Touch Screen Module

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The tPad features an 8-inch Amorphous-TFT-LCD panel. The LCD Touch Screen module offers
resolution of (800x600) to provide users the best display quality for developing applications. The
LCD panel supports 18-bit parallel RGB data interface.
The tPad is also equipped with an Analog Devices AD7843 touch screen digitizer chip. The
AD7843 is a 12-bit analog to digital converter (ADC) for digitizing x and y coordinates of touch
points applied to the touch screen. The coordinates of the touch points can be read through the serial
port interface on the AD7843.
To display images on the LCD panel correctly, the RGB color data along with the data enable and
clock signals must act according to the timing specification of the LCD touch panel as shown in
Table 3-1.
Table 3-2 gives the pin assignment information of the LCD touch panel.
Table 3-1 LCD timing specifications
Parameter
Symbol
Values
Unit
Min.
Typ.
Max.
CLK Frequency
FCPH
-
39.79
-
MHz
CLK Period
FCPH
-
25.13
-
Ns
CLK Pulse Duty
FCWH
40
50
60
%
DE Period
FDEH+ TDEL
1000
1056
-
TCPH
DE Pulse Width
FDH
-
800
-
TCPH
DE Frame Blanking
FHS
10
28
110
FDEH+TDEL
DE Frame Width
FEP
-
600
-
FDEH+TDEL
OEV Pulse Width
TOEV
-
150
-
TCPH
OKV Pulse Width
TCKV
-
133
-
TCPH
DE(internal)-STV Time
T1
-
4
-
TCPH
DE(internal)-CKV Time
T2
-
40
-
TCPH
DE(internal)-OEV Time
T3
-
23
-
TCPH
DE(internal)-POL Time
T4
-
157
-
TCPH
STV Pulse Width
-
-
1
-
TH
Note: THS + THA < TH
Table 3-2 Pin assignment of the LCD touch panel
Signal Name
FPGA Pin No.
Description
I/O Standard
LCD_DIM
PIN_P27
LCD backlight enable
2.5V
LCD_NCLK
PIN_V24
LCD clock
2.5V
LCD_R0
PIN_V26
LCD red data bus bit 0
2.5V
LCD_R1
PIN_R27
LCD red data bus bit 1
2.5V