User's Manual

GE864- QUAD Har dwar e User Guide
1vv0300872 Rev.1 2010-04-02
- All Rights Reserved. Page 40 of 77
9. Serial Ports
The serial port on the Telit GE864-QUAD is the core of the interface between the
module and OEM hardware.
2 serial por ts are available on the module:
MODEM SERIAL PORT
MODEM SERIAL PORT 2 (DEBUG)
9.1. Modem Serial Port
Several configurations can be designed for the ser ial port on the OEM hardware, but
the most common are:
RS232 PC com port
Micro controller UART @ 2.8V – 3V (Universal Asynchr onous Receive
Transmit)
Micro controller UART@ 5V or other voltages different from 2.8V
Depending fr om the type of serial port on the OEM hardware a level translator circuit
may be needed to make the system wor k. The only configur ation that does not need a
level translation is the 2.8V UART.
The serial port on the GE864-QUAD is a +2.8V 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 the GE864-QUAD UART are the CMOS levels:
Absol ute Maximum Ratings – Not Functional
Par am eter
Min
Max
Input level on any
digital pad when on
-0.3V
+3.6V
Input voltage on
analog pads when on
-0.3V
+3.0 V