CC864-DUAL Hardware User Guide
1vv0300791 Rev 4.4 – 2011-01-26
Reproduction forbidden without Telit Communications S.p.A’s. written authorization - All Rights Reserved.
Page 35 of 63
Operating Range – Interface levels (1.8V CMOS):
Parameter
Min
Max
VIH (input high level)
1.2V
2.1V
VIL (input low level)
-0.3V
0.63V
VOH (output high level)
1.35V
1.8V
VOL (output low level)
0.0V
0.45V
3.8. Serial
Interfaces
Serial ports on the CC864-DUAL function as the interface between the module and
User Application.
There are two main types of serial ports on the module: UART and USB.
The CC864-DUAL has one main UART that can be used for control and data transfer.
In addition, the module has a USB port that can function as the main control interface
for the host application.
NOTE:
To access the module and to allow in-circuit reprogramming of the module’s
firmware, the USB port must be made available. This is generally a requirement for
wireless carrier approval testing as well. The application controlling the device may
be placed into tri-state, disconnected, or act as a gateway for the serial data when
reprogramming occurs.
All application designs should include a means to reprogram the module!
3.8.1.
UART - Serial Interface
The CC864-DUAL UART functions as the controlling interface between the module
and the host hardware.
Depending on the host hardware serial port implementation, a level translator circuit
may be required. The only configuration that does not require level translation is
interfacing to a 2.8V UART.
There is one UART port on the CC864-DUAL. It differs from the standard PC
RS232C in signal polarity (where RS232 is reversed) and levels.
The UART can be used as the module’s serial data port for test and debug using AT
commands, and can support additional interface functions such as an external
keypad or ringer.
The following table lists the signals of the CC864-DUAL UART and the
corresponding RS-232 signals:
RS232
Pin
No
Signal
Pin No
Name
Usage
1
C109/DCD
32
Data Carrier
Output from the CC864-DUAL
