User's Manual

UE866 HARDWARE USER GUIDE 1vv0301157 Rev.7 • 2015-04-17 26 of 68
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5.2 Power on
The UE866 will automatically power on itself when VBATT & VBATT_PA are applied to the module.
VAUX / PWRMON pin will be at the high logic level and the module can be considered fully operating
after 5 seconds. The following flow chart shows the proper turn on procedure:
NOTE:
The power supply must be applied either at the same time on pins VBATT and
VBATT_PA.
To guarantee a correct module’s start-up please check that the Power Supply
is with a level >3.22V within 21mS.
PWRMON=ON
?
“Modem ON Proc”
START
PWR Supply ON
& > 3.22V?
PWRMON=ON
?
Delay = 300 ms
AT Init Sequence
Enter AT<CR>
N
Delay 1s – 5s for Low Voltage
Operating
Y
Y
N
Y
Delay = 1 sec
N
Start AT CMD
AT Answer in
1sec?
Modem Reset Proc
N
Y