User's Guide

UC864-E-AUTO / AWS-AUTO Hardware User Guide
1vv0300795 Rev.11 – 2010/11/18
Reproduction forbidden without Telit Communications S.p.A’s. written authorization - All Rights Reserved. Page 37 of 78
8.1. Reset Signal
Signal
SignalSignal
Signal Function
FunctionFunction
Function I/O
I/OI/O
I/O PIN Number
PIN NumberPIN Number
PIN Number
RESET Phone reset I 54
RESET is used to reset the UC864-E-AUTO / AWS-AUTO module. Whenever this
signal is pulled low, UC864-E-AUTO / AWS-AUTO is reset. When the device is reset it
stops all operations. After the release of the reset UC864-E-AUTO / AWS-AUTO is
unconditionally shut down, without doing any detach operations from the network
where it is registered. This behavior is not a proper shutdown because the device is
requested to issue a detach request on turn off. For this reason, the Reset signal
must not be used for 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 always a proper power-on
reset sequence. There is 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.
Reset Signal Operating levels:
Signal
SignalSignal
Signal Min
MinMin
Min Max
MaxMax
Max
RESET Input high 2.0V* 2.6V
RESET Input low 0V 0.2V
* 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, it must always be connected
with an open collector transistor to permit the internal circuitry the power on reset
and under voltage lockout functions.
NOTE:
NOTE: NOTE:
NOTE:
Do not use this signal to power off UC864-E-AUTO / AWS-AUTO. Use the ON/OFF
signal to perform this function or the AT#SHDN command.