TC45 TC45 JAVA User's Guide
Confidential / Released
TC45_JAVA User's Guide_V02
Page 23 of 72
30.06.2003
4.2 Interfaces
4.2.1 ASC0 - Serial device
ASC0, an Asynchronous Serial Connection, is a 9-wire serial interface. It is described in the
Hardware Interface Description [5]. Without a running Java application the module can be
controlled by sending AT commands via ASC0. Furthermore ASC0 is designed for
transferring files from the development PC to the module and for controlling the module with
AT commands. When a Java application started, ASC0 is used for debugging from the
development environment, as System.out for Java applications running on the module (see
Section 4.4.1).
4.2.2 General Purpose I/O
There are nine I/O pins that can be configured for general purpose I/O. When JAVA User's
Guide starts up, all 9 pins of both interfaces are set, by default, to high-impedance state for
use as input.
The pins are divided into two GPIO pin groups. Pin group 0, (GPIO 0 – 3), is the set also
used as ASC1. The second pin group, (GPIO 4 – 8), shares resources with the DAI. Pins 0 -
3 can be configured either as general purpose I/O (GPIO) or ASC1 but not both. The same
for pins 4 - 8, they can be configured either as GPIO or as DAI. See [4] and [5] about
configuring the pins.
4.2.3 ASC1
ASC1 is the second serial interface on the module. This is a 4-pin interface (RX, TX, RTS,
CTS). It can be used as a second AT interface when a Java application is not running or by
a running Java application as an RS-232 port, refer to Java doc [6]. These four pins can be
configured as general purpose I/O when not used as ASC1. The default status of ASC1 is
inactive.
4.2.4 Digital Audio Interface (DAI)
To support the DAI function, the TC45 has a five-line serial interface with one input data
clock line and input/output data and frame lines. These five pins can also be configured as
general purpose I/O when not used as DAI. Refer to AT Command Set [4] and Hardware
Interface Description document [5] for more information.
