Network Status Indication; General Purpose Input Output (Gpio) - SIM Tech SIM900D HD Manual

SIM900D Hardware Design

3.15 Network Status Indication

The NETLIGHT can be used to drive a network status indication LED lamp. The working state of this pin is
listed in following table:
Table20: Working state of the NETLIGHT
State
Off
64ms On/ 800ms Off
64ms On/ 3000ms Off
64ms On/ 300ms Off
Provide a reference circuit for user, shown as following figure:

3.16 General Purpose Input Output (GPIO)

SIM900D provides a limited number of General Purpose Input/Output signal pin. The output and input voltage
level of the GPIO can be set by AT command. For more details, please refer to document [1]
SIM900D_HD_V1.02
SIM900D function
SIM900D is not running
SIM900D does not find the network
SIM900D find the network
GPRS communication
MODULE
NETLIGHT
Figure28: Reference circuit of NETLIGHT
48
VBAT
300R
4.7K
47K
09.04.2010