User's Manual

GSM/GPRS Module Series
M85 Hardware Design
M85_Hardware_Design Confidential / Released 27 / 88
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].
2. AT command response indicates module is turned on successfully, or else the module fails to be
turned on.
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
K1
Close to K1
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)
EMERG_OFF
(INPUT)
54ms
STATUS
(OUTPUT)
800ms
>1s
OFF
BOOTING
MODULE
STATUS
RUNNING
T
1
Figure 8: Turn-on Timing