SIM900 Hardware Design
C3
SIM_CLK SIM Card Clock
C4
GND Connect to GND
C5
GND Connect to GND
C6
VPP Not connect
C7
SIM_DATA SIM Card data I/O
C8
SIM_PRESENCE Detect SIM Card Presence
3.11 LCD Display Interface
SIM900 provides a serial LCD display interface that supports serial communication with LCD device. When
used as LCD interface, the following table is the pin definition. LCD interface timing should be united with
the LCD device.
Table 15: Pin define of the LCD interface
Pin Name Pin Number Function
DISP_CLK 11 Display clock for LCD
DISP_DATA 12 Display data output
DISP_D/C 13 Display data or command select
DISP_CS 14 Display enable
Note: This function is not supported in the default firmware. There must be some customized firmware if you
want. Please contact SIMCom for more details.
3.12 Keypad Interface
The keypad interface consists of 5 keypad column outputs and 5 keypad row inputs. The basic configuration is 5
keypad columns and 5 keypad rows, giving 25 keys.
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