User's Manual

UL865-N3G Hardware User Guide
1VV0301177 Rev 2– 2015-04-20
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Reserved. Page 40 of 70
Mod. 0805 2011-07 Rev.2
8.5. Reset signal
Signal Function I/O pin
RESET* Phone reset I 47
RESET* is used to reset the UL865-N3G V2. Whenever this signal is pulled low, the UL865-
N3G V2 is reset. When the device is reset it stops any operation. After the release of the reset
UL865-N3G V2 is unconditionally shut down, without doing any detach operation from the
network where it is registered. This behavior is not a proper shut down because any GSM
device is requested to issue a detach request on turn off. For this reason the Reset signal must
not be used to normally shutting down the device, but only as an emergency exit in the rare
case the device remains stuck waiting for some network response.
The RESET* is internally controlled on start-up to achieve a proper power-on reset sequence,
so there's no need to control this pin on start-up. It may only be used to reset a device already
on that is not responding to any command.
NOTE:
Do not use this signal to power OFF the UL865-N3G V2. Use the ON/OFF procedure to
perform this function.
Reset Signal Operating levels:
Signal Min Max
RESET* Input high 1.5V(NOTE1) 1.9V
RESET* Input low 0V 0.35V
(NOTE1) this signal is internally pulled up so the pin can be left floating if not used.
If unused, this signal may be left unconnected. If used, then it must always be connected with
an open collector transistor, to permit to the internal circuitry the power on reset and under
voltage lockout functions.