1 reset signal – Rainbow Electronics GM862-QUAD-PY User Manual

Page 15

GM862-QUAD / PY Hardware User Guide

1vv0300748 Rev. 5 - 20/09/07

page 15 of 68

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

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.