Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
13
Figure 3-6
VRTC reference design
3.1.4 Power-On/Off Control and Procedure
Prior to turning on the module, power on the host MCU and finish the UART initialization. Otherwise
conflictions may occur during initialization, due to unstable conditions.
ON/OFF is a low level pulse active input, used to turn on or off the module.
Power-On Procedure
While the module is off, drive the ON/OFF pin to ground for at least
1.2 second
and then release, the
module will start. An unsolicited message (+EIND: 128) will be sent to host through UART port, indicating
that the module is powered on and can respond to AT commands.
When you design your program, you can use the unsolicited message (+EIND: 128) to check whether the
module is started or reset improperly.
Figure 3-7
Power-on procedure
Backup
battery
GPRS Module
RTC
Circuit
Capacitor
VRTC
1.5K
VBAT
ON/OFF
VDD_EXT
UART
1.2s
3s
300 ms
