User's Manual

UC864-G Hardware User Guide

DRAFT

- 29/10/07

8 Serial Ports

The serial port on the Telit UC864-G 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)

8.1 MODEM 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 @ 2.8V - 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 2.8V

UART.

The serial port on UC864-G 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-G UART are the

CMOS levels:

Absolute Maximum Ratings -Not Functional

UC864-G

Parameter

Min Max

Input level on any

digital pin when on

-0.3V +3.0V

Input voltage on

analog pins when on

-0.3V +3.0 V

Operating Range - Interface levels

UC864-G

Level

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