User's Manual

Telit TRIZIUM Product Description

80264ST10007a Rev. 4– 09/09/04

2.12.1 Reset signal

Signal Function I/O Pin

RESET Phone reset I/O 23 (connector SO301)

RESET is used to reset the Telit TRIZIUM module. Whenever this signal is pulled low, the TRIZIUM

is reset. When the device is reset it stops any operation and after the release of the reset it shuts

down, without doing any detach operation from the network where it is registered to. 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 stucked waiting for some network

response.

The RESET is internally controlled on start-up to achieve always 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 Telit TRIZIUM module. Use the ON/OFF signal

(Pin 17 of SO301) to perform this function or the AT#SHDN command.

Reset Signal Operating levels:

Signal Min Max

RESET Input high 2.2V* 3.3V

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, then it must always be connected with an open collector

transistor, to permit to the internal circuitry the power on reset and undervoltage lockout functions.