GSM/GPRS Module
M85 Hardware Design
M85_Hardware_Design Confidential / Released 28 / 92
―AT‖ or ―at‖ string until receiving ―OK‖ string from the module. Then enter ―AT+IPR=x;&W‖ to set a fixed
baud rate for the module and save the configuration to flash memory of the module. After these
configurations, the URC ―RDY‖ would be received from the UART Port of the module every time when the
module is powered on. For more details, refer to the section ―AT+IPR‖ in
document [1]
.
The other way to control the PWRKEY is through a button directly. A TVS component is indispensable to
be placed nearby the button for ESD protection. For the best performance, the TVS component must be
placed nearby the button. When pressing the key, electrostatic strike may generate from finger. A
reference circuit is shown in the following figure.
PWRKEY
S1
Close to
S1
TVS
Figure 7: Turn on the module with a button
The turn-on timing is illustrated as the following figure.
VDD_EXT
(OUTPUT)
V
IL
<0.1*VBAT
V
IH
> 0.6*VBAT
VBAT
PWRKEY
(INPUT)
54ms
>1s
T
1
OFF
BOOTING
MODULE
STATUS
RUNNING
EMERG_OFF
(INPUT)
Figure 8: Turn-on Timing
Quectel
Confidential