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Functional Description
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A PS/2 keyboard and mouse interface via transition module
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A parallel printer port interface
Asynchronous Serial Ports
The Super I/O device provides two UART devices which are compatible
with standard 16450 or 16550A UARTs. The default configuration assigns
COM1 to IRQ4 and COM2 to IRQ3 of the PBC. The default configuration
can be changed by programming the ISASIO device accordingly.
The COM1 port is wired as an RS-232 interface to a PC compatible DB9
connector on the front panel and it is also routed to the transition module
via J3. COM2 is wired as an RS232 interface and is routed to the J3 I/O
connector for transition module I/O.
For additional programming information, refer to the PCI and ISA bus
discussions in the MCP750 Programmer’s Reference Guide
(MCP750A/PG) and to the vendor documentation for the ISASIO device.
Parallel Port/Printer Interface
The parallel port is a full IEEE1284 bidirectional parallel port/printer
interface that supports standard enhanced and extended port modes. All
parallel I/O interface signals are routed to the transition module that
includes series damping resistors.
Hardware initializes the parallel port as PPT1 with an ISA IO base address
of $3BC. This default configuration also assigns the parallel port to
Peripheral Bus Controller (PBC) interrupt request line IRQ7. The default
configuration can be changed by reprogramming the ISASIO device. For
additional programming information, refer to the PCI and ISA bus
discussions in the MCP750 Programmer’s Reference Guide and to the
vendor documentation for the ISASIO device.
Floppy Disk/Tape Drive Controller
The ISASIO device incorporates a PS/2-compatible low- and high-density
disk drive controller for use with an optional external disk drive. The drive
interfaces with the ISASIO controller via the transition module.
