rtd CMV6486DX100HR, Руководство пользователя

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Using Virtual Devices
The cpuModule is designed for use in industrial environments as a stand-alone module, without ex-
ternal peripherals. Nevertheless, it may be necessary to interface a cpuModule with I/O devices like
a keyboard, monitor, or floppy or hard drive, especially for set-up or maintenance.
The cpuModule is therefore provided with “Virtual Devices”, which allows you to access a key-
board, monitor, and floppy disks without directly connecting them to the PC/104 bus of the module.
Instead, the cpuModule serial port is connected to the serial port of a PC or AT “host” computer. The
host computer’s keyboard, monitor, and floppy disks can then be made available to the cpuModule.
You can then boot from the host’s floppy drives, edit and debug programs using the host’s keyboard
and monitor, and so on.
There are two limitations when using Virtual Device mode:
• programs must operate only in text mode
• program screen input/output must use only BIOS calls
Applications which use graphics modes or directly access hardware (video memory, the keyboard,
or the disk drives) will not work properly.
To use Virtual Devices mode, you will need:
• a PC or AT compatible “host” computer with a serial port
• the connection program (SERRX.EXE) available on the host computer
• a "null-modem" cable with the transmit data, receive data, and ground pins connected
• the cpuModule
There are two ways to initiate Virtual Device mode. You can enable the mode by using the cpuMod-
ule Setup program, or by jumpering pins on the first serial port connector of the cpuModule. Please
note that behavior differs slightly depending on how Virtual Device mode is initiated. The following
sections discuss the two methods.
NOTE! Virtual Devices mode is intended for use during development, testing,
and servicing of the cpuModule. It is not intended for use during normal
operation of the cpuModule. The overhead required by Virtual Devices
will probably cause unacceptable performance while running an
application.
If you require user I/O through the serial port, we strongly recommend
you implement your own serial I/O or use a commercial software
product intended for this purpose.