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Advantech SOM-ETX Design Guide
LCDG7
TTL Green Data 7
C09 DE
I
Data enable signal
C52 SHFCLK
I
Clock signal
C46 LCDON
I
Power enable signal
C44 BACKON# I
Backlight enable signal
5.6.2 Design Guideline
Figure 5.18 and Figure 5.19 show LVDS LCD and TTL LCD connections. And Table
5.14 shows LVDS and TTL pin-out table.
LVDS
LCD
Connector
120 Ohm
@100MHz
SOM-ETX
10~33 Ohm
VGA
Damping
LVDS+
LVDS-
Carryboard
Inverter
Connector
BACKON
VDD
LCDON
Power
Transfer
+3.3V
+5V
Bead
30Ohm
@100Mhz
Figure 5-18 LVDS LCD Connections
TTL LCD
Connector
120 Ohm
@100MHz
SOM-ETX
10~33 Ohm
VGA
Damping
TTL
10pF
Buffer IC
for Level
Shift
Carryboard
BACKON
Inverter
Connector
LCDON
VDD
Power
Transfer
+3.3V
+5V
Bead
30Ohm
@100Mhz
Figure 5-19 TTL LCD Connections
Note:
*All SOM-ETX TTL LCD signal level is 3.3V. For 5V signal level TTL LCD, Advantech
suggests add a Buffer IC (e.g. 74AC374) to convert the signal level by power support
voltage. If you need to support 3.3 and 5V level LCD, Buffer IC and 0 Ohm resistor
co-layout is suggested.
*For detail circuit, please see the Advantech reference schematic.
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Chapter 5 Carrier Board Design Guidelines