User's Guide

HE863 Family Hardware User Guide
1vv0300891 Rev.5
- 2011-03-18
Reproduction forbidden without Telit Communications S.p.A’s. written authorization - All Rights
Reserved. Page 72 of 89
12.1. Logic Level Specifications
Where not specifically stated, all the interface circuits work
at 1.8V CMOS logic levels.
The following table shows the logic level specifications used
in the HE863 Family interface circuits:
For 1.8V CMOS signals:
Absolute Maximum Ratings -Not Functional
Parameter Min Max
Input level on
any digital pin
when on
-0.3V +3.6V
Input voltage
on analog pins
when on
-0.15V +3.0 V
Operating Range - Interface levels
Level Min Max
Input high
level
1.26V 2.0 V
Input low level -0.2V 0.36V
Output high
level
1.6V 1.8V
Output low
level
0V 0.2V
12.2. 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
1.8V CMOS levels of the GPIO.
If the digital output of the device is connected with the GPIO
input, the pad has interface levels different from the 1.8V
CMOS. It can be buffered with an open collector transistor
with a 47KΩ pull-up resistor to 1.8V.
12.3. Using a GPIO Pad as Output
The GPIO pads, when used as outputs, can drive 1.8V CMOS
digital devices or compatible hardware. When set as outputs,