User's Guide

UL865 Hardware User Guide
1VV0301050 Rev 2 – 2013-10-09
The UL865 will automatically power on itself when VBATT & VBATT_PA are applied
to the module.
V_AUX / 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:
Modem ON Proc.
PWR supply ON
and >3.22V?
Y
Delay 1s - 5s for Low
Voltage Operating
Y
Modem Reset Proc.
AT init sequence.
N
Start AT CMD.
N
PWMON = ON?
Y
PWMON = ON?
Delay 300mS
Enter AT<CR>
AT answer in
1second ?
N
Y
N
Delay 1s