4.2.2
I/O Subsystem
The I/O subsystem, implemented with an NS87334 VJG Super I/O
Controller Chip, provides for such functions as internal Hard Drive control,
floppy drive control, and serial and parallel ports. The Super I/O Controller
includes the following features:
•
100 percent compatible with ISA, EISA, and Micro-channel architectures
•
Built-in Floppy Disk Controller
•
Software compatible with the DP8473, the 765A and N82077
•
16-byte FIFO (default disabled)
•
Burst and Non-burst modes
•
Perpendicular Recording drive support
•
New high-performance internal digital data separator (no external
filter components required)
•
Low-power CMOS with enhanced power-down mode
•
Automatic media-sense support
•
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
•
Compatible 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 IDE controller
•
Provides a complete IDE interface with DMA control (except for
optional buffers)
Theory of Operation
4-3