User Manual

GM862-QUAD / PY Hardware User Guide

1vv0300748 Rev. 5 - 20/09/07

Current characteristics

Level Typical

Output Current 1mA

Input Current 1uA

4.3.1 Reset signal

Signal Function I/O Pin

RESET Phone reset I 23 (connector SO301)

RESET is used to reset the GM862-QUAD/PY modules. Whenever this signal is pulled low, the GM862 is

reset. When the device is reset it stops any operation. After the release of the reset GM862-QUAD

and GM862-QUAD-PY are unconditionally rebooted, without doing any detach operation from the

network where it is registered. This behaviour 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 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 GM862-QUAD-PY. 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 2.0V* 2.2V

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 under voltage

lockout functions.