User's Manual

GM862-QUAD / PY Hardware User Guide

1vv0300748 Rev. 1 - 24/10/06

8.2 Using a GPIO pin as INPUT

The GPIO pins, when used as inputs, can be connected to a digital output of another device and

report its status, provided this device has interface levels compatible with the 2.8V CMOS levels of the

GPIO.

If the digital output of the device to be connected with the GPIO input pin has interface levels different

from the 2.8V CMOS, then it can be connected to GPIO1 or can be buffered with an open collector

transistor, provided a 47KΩ pull-up resistor is connected as seen in the paragraph 5.2 5V UART level

translation.

8.3 Using a GPIO pin as OUTPUT

The GPIO pins, when used as outputs, can drive 2.8V CMOS digital devices or compatible hardware.

When set as outputs, the pins (except from GPIO2 which is Open Collector) have a push-pull output

and therefore the pull-up resistor may be omitted.

The GPIO2 pin, since it is an Open Collector output needs an external pull-up resistor.

8.4 Using the RFTXMON Output GPIO5

The GPIO5 pin, when configured as RFTXMON Output, is controlled by the GM862-QUAD / PY

module and will rise when the transmitter is active and fall after the transmitter activity is completed.

For example, if a call is started, the line will be HIGH during all the conversation and it will be again

LOW after hanged up.

8.5 Using the Alarm Output GPIO6

The GPIO6 pin, when configured as Alarm Output, is controlled by the GM862-QUAD / PY module

and will rise when the alarm starts and fall after the issue of a dedicated AT command.

This output can be used to power up the GM862-QUAD / PY controlling microcontroller or application

at the alarm time, giving you the possibility to program a timely system wake-up to achieve some

periodic actions and completely turn off either the application and the GM862-QUAD / PY during sleep

periods, drammatically reducing the sleep comsumption to few μA.

In battery powered devices this feature will greatly improve the autonomy of the device.