Priority Interrupt
Number Interrupt Source
17 IRQ7 Parallel Port
nNote: A PCMCIA card can use IRQ 3, 4, 5, 7, 9 and 11 as long as it does not
conflict with the interrupt address of a ny other device.
4.2.2 I/O Subsystem
The I/O subsystem, implemented with an SMC37C655IR Super I/O
Controller Chip, provides for such functions as internal floppy drive control,
serial and parallel ports and support for the Serial Infrared port. The Super
I/O Controller includes the following features:
•100 percent compatible with ISA, EISA, and micro-channel architectures
• Built-in floppy disk controller
•Two UARTs
•Software compatible with the PC16550A and PC16450
•MIDI compatible
•Infrared support on UART2 (IRDA-compliant)
•Bidirectional Parallel Port
•Enhanced Parallel Port (EPP) compatible
•Extended Capabilities Port (ECP) compatible, including level 2
support
•Bidirectional under either software or hardware control
•Compatbile with ISA, EISA, and Micro Channel architectures
•Ability to multiplex FDC signals on parallel port pins for
external FDD
•Includes protection circuit against damage caused when
printer is powered up, or operated at higher voltages
•Integral address decoder- provides selection of all primary and
secondary ISA addresses including COM1-4 and LPT1-3.
•Enhanced Power Management Fun ction
•Enhanced programmable power-down and wake-up modes
Theory of Operation 4-5