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SIM548C Hardware Design
GPS_VANT
I
The external DC power supply for an
active GPS antenna. It’s input voltage
depends on the type of chosen active
antenna, for the 5V type, it has to be
connected to 5V external power
supply; for the 3V type, it can be
connected to the GPS_VCC_RF pin
directly which provides 2.85V DC.
Imax=25mA
Vmax=5V
Vmin=2.85V
GPS_VCC_RF
O
The optional power supply for 3.0V
type active antenna.
Vmax=2.9V
Vmin=2.8V
Vnorm=2.85V
Imax=25mA
GND
Ground, shared with GSM part
Dual serial interface
PIN NAME
I/O
DESCRIPTION
DC CHARACTERISTICS
GPS_TXA
O
Serial data output for port A
GPS_RXA
I
Serial data input for port A
GPS_TXB
O
Serial data output for port B
GPS_RXB
I
Serial data input for port B
VILmin=-0.3V
VILmax=0.84V
VIHmin=1.96V
VIHmax= 3.1
VOLmin=GND
VOLmax=0.7V
VOHmin=2.1V
VOHmax=2.8V
Control signals
PIN NAME
I/O
DESCRIPTION
GPS_BOOTSEL
I
For re-programming the Flash, it
must be set to High
GPS_M-RST
I
Reset pin, active low. If used, it
causes the module to reset; if not
used, leave it open .
Note, if this pin is pulled
down by a GPIO, then the
GPIO must have the
capability of inputting
1.5mA current.
GPS_TimeMark
O
1 PPS timemark output for
synchronizing to within 1
microsecond of GPS time.
If not used, leave it open.
SIM548C_HD_V1.01
09.05.2008
65