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Functional Description
2
Super I/O Device
The VP22 uses the Super I/O (SIO) device to provide two asynchronous
serial ports, a peripheral parallel port, a PS/2 floppy port, PS/2
keyboard/mouse ports and an IrDA header.
Asynchronous Serial Ports
Two 16550-compatible asynchronous serial ports are supported on the
VP22 motherboard. The EIA-232 drivers and receivers reside onboard.
COM1 is routed to an industry-standard DB-9 connector accessible from
the rear panel and COM2 is routed to an optional 10-pin header. Both ports
are configured as DTE. Maximum data rate on any port is 115.2K baud.
Firmware initializes the two serial ports as COM1 and COM2 with ISA I/O
base addresses of 3F8h and 2F8h respectively. This default configuration
also assigns COM1 to IRQ4 and COM2 to IRQ3.
Peripheral Parallel Port
All parallel I/O interface signals are routed to an industry-standard DB-25
connector, accessible from the rear panel. This port supports the full
IEEE-1284 capability, which provides the basic printer interface.
Firmware initializes the parallel port as LPT1 with ISA I/O base address of
378h. This default configuration also assigns the parallel port to IRQ7.
PS/2 Floppy Port
The floppy port is configured for PS/2 compatibility and supports both the
legacy 34-pin header and the compact floppy disk drive (FDD) connector.
Up to two floppy drives are supported.
Keyboard and Mouse Ports
Two 6-pin circular DIN connectors are located on the rear panel of the
VP22 motherboard for the keyboard and mouse connections. The power
provided to the keyboard and mouse is protected by a polyswitch rated at
1.1 A.
