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USB COM Port Emulation Software Development Option for the
micro-line^® C6412Compact DSP / FPGA Platform.

	implements the CDC/ACM device class (COM port emulation)
	supports up to 3 COM ports
	well-known standard communication interface
	operation using Windows' built-in COM port drivers possible
	documentation and application examples included
	basic development kit required (such as DSP Development Kit)

The USB CDC/ACM Library
The USB CDC/ACM Library uses an embedded USB device stack together with a set of predefined descriptors. These descriptors define a unique device class for the C6412Compact together with three instances of the CDC/ACM device classe. The CDC/ACM device class acts as a classic COM port to a host PC. Usage of the library is straightforward. No specific USB knowledge is required to set up operation. Data transfers are implemented using simple read/write functions that operate on a queue of buffers.

Host Side Driver Support
When USB operation has started, the C6412Compact identifies itself to a USB host as a CDC/ACM device. A USB host that wants to communicate with the C6412Compact must have a suitable driver installed. There are three choices for drivers:

When using a single COM port, the built-in windows driver (usbser.sys) can be used. A suitable install script is included in the distribution.

As an alternative, an optimized driver (higher data rates and more reliable operation) is included as a 4 hours run-time limited demo version.

When using multiple COM ports, the optimized driver together with a multi-interface driver must be used. The multi-interface driver (demo version) is also included in the distribution. Newer Windows versions starting at Windows Vista, SP1 may also support multiple instances using the built-in drivers.

Application Examples
Two application examples are included. Both implement loop-back operation which can easily be tested with a terminal program, such as Hyperterminal. One application example does a local loopback on the first emulated COM port. The screenshot below shows a sample session with the terminal output on the left and the debugging messages of the application example (also in a terminal window) on the right.

The second example uses all three COM ports. The first two COM ports are cross connected, so that the input of one port appears at the output of the other port. The third COM port has no USB counterpart, therefore it is routed to the native COM port (RS-232 interface / main UART) of the C6412Compact. The screenshot below shows a sample session where three emulated COM ports and one native COM port are involved.

Software Development Tools
For developing USB CDC/ACM applications on the C6412Compact, the following items are required:

Basic software development kit for the C6412Compact, e.g. DSP Development Kit

USB COM Port Emulation Software Development Option

Code Composer Studio from Texas Instruments

Related products

DSP Board	C6412Compact
Basic Software Development Kits	DSP Development Kit IEEE1394 Development Kit DCAM Frame Capture Development Kit DCAM Video Processing Development Kit
Other Software Development Options	Ethernet Software Development Option USB Software Development Option (bulk transfers)
Development tools	Code Composer Studio USB JTAG emulator Parallel port JTAG emulator PCI JTAG emulator
FPGA Development	FPGA development package

For more information about the
USB COM Port Emulation Software Development Option
and pricing details:

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