Telit Wireless Solutions UC864 manual Serial Ports, Absolute Maximum Ratings Not Functional

UC864-E Hardware User Guide

1vv0300766a Rev.1 - 31/01/08

8 Serial Ports

The serial port on the Telit UC864-E is the interface between the module and OEM hardware.

2 serial ports are available on the module:

•MODEM SERIAL PORT

•MODEM SERIAL PORT 2 (DEBUG)

8.1MODEM SERIAL PORT

Several configurations can be designed for the serial port on the OEM hardware, but the most common are:

•RS232 PC com port

•microcontroller UART @ 2.6V - 3V (Universal Asynchronous Receive Transmit)

•microcontroller UART @ 5V or other voltages different from 2.8V

Depending from the type of serial port on the OEM hardware a level translator circuit may be needed to make the system work. The only configuration that doesn't need a level translation is the 2.6V UART.

The serial port on UC864-E is a +2.6V UART with all the 7 RS232 signals. It differs from the PC- RS232 in the signal polarity (RS232 is reversed) and levels. The levels for UC864-E UART are the CMOS levels:

Absolute Maximum Ratings - Not Functional

Parameter	UC864-E
	Min	Max
Input level on any	-0.3V	+3.0V
digital pin when on
Input voltage on	-0.3V	+3.0 V
analog pins when on

Operating Range - Interface levels

Level	UC864-E
	Min	Max
Input high level	2.0V	2.9 V
Input low level	-0.3V	0.6V
Output high level	2.2V	2.6V
Output low level	0V	0.35V

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