Smart Machine Smart Decision
SIM868_Series_Hardware_Design_V1.06
49
2017-07-13
Figure 43: Power on/off GNSS
GPS_VBAT
GNSS_EN
GPS_TX
(input)
T
1
=1s
NEMA
V_GPS
T
2
=1.6s T
2
=1.9s
Figure 44: Timing of power on GNSS
GPS_VBAT
GNSS_EN
GPS_TX
(input)
T
1
=3.4s
NEMA
V_GPS
Figure 45: Timing of power off GNSS
6.5.
Serial Port of GNSS
GNSS UART interface support NMEA output and PMTK command input.
Table 30: Serial port pin definition
Table 31: Serial port characteristics
Symbol
Min
Max
Unit
V
IL
-0.3
0.7
V
V
IH
2.1
3.0
V
V
OL
-
0.4
V
Pin name
Pin number Function
Serial port
GPS_TXD
61
Transmit data
GPS_RXD
62
Receive data
SIMCOM
CONFIDENTIAL
FILE
