Smart Machine Smart Decision
SIM868_Series_Hardware_Design_V1.06 22 2017-07-13
4. Application Modes of SIM868
4.1. All-in-one Mode
In all-in-one mode, UART2 of GSM is connected with GNSS_UART. It’s convenient for communication
between GSM and GNSS, such as control GNSS, firmware upgrade and download EPO data.
As the Figure 6, a 10K resistor should be added between GPIO1 and GNSS_EN pin.
In this mode, GNSS part can be enabled through AT command“AT+C GNSP WR=1”and disabled through AT
command“AT+CG NSPWR =0”. GSM and GNSS’s firmware could be upgraded through UART1 port or USB
with high-speed.
Module
GNSS_RXD
GNSS_TXD
UART2_RXD
UART2_TXD
VRTC
VRTC
MCU
UART1_TXD
UART1_RXD
RXD
TXD
GSM_VBAT
LDO
Adapter
5V
4V
GPS_VBAT
GNSS_EN
OUT
PWRKEY
V_GPS
LDO
R101
10K
GPIO1
USB
Figure 6: All-in-one Mode Diagram