User's Manual

Table Of Contents

GC864 Hardware User Guide

1vv0300874 Rev.0 – 2010-01-25

11.2. Using a GPIO Pad as INPUT

The GPIO pads, 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 pad has

interface levels different from the 2.8V CMOS, then it can be buffered with an open

collector transistor with a 47K pull up to 2.8V, this pull up must be switched off when

the module is in off condition.

11.3. Using a GPIO Pad as OUTPUT

The GPIO pads, when used as outputs, can drive 2.8V CMOS digital devices or

compatible hardware. When set as outputs, the pads have a push-pull output and

therefore the pull-up resistor may be omitted.

The illustration below shows the base circuit of a push-pull stage:

11.4. Using the RF Transmission Control GPIO4

The GPIO4 pin, when configured as RF Transmission Control Input, permits to disable

the Transmitter when the GPIO is set to Low by the application.

In the design is necessary to add a resistor 47K pull up to 2.8V, this pull up must be

switched off when the module is in off condition.

11.5. Using the RFTXMON Output GPIO5

The GPIO5 pin, when configured as RFTXMON Output, is controlled by the GC864-

QUAD V2 / GC864-DUAL V2 module and will rise when the transmitter is active and

fall after the transmitter activity is completed.

VDD

GPIO7