3-10
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Functional Description
3
Disk 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 base board connector J4, which
relays both power and control signals.
The ISASIO disk drive controller is compatible with the DP8473, 765A,
and N82077 devices commonly used to implement floppy disk controllers.
Software written for those devices may be used without change to operate
the ISASIO controller. The ISASIO device may be used to support any of
the following devices:
❏
3
1
/
2
-inch 1.44MB floppy disk drive
❏
5
1
/
4
-inch 1.2MB floppy disk drive
❏
Standard 250kbps to 2Mbps tape drive system
Keyboard and Mouse Interface
The National Semiconductor PC87308 ISASIO chip used to implement
certain segments of the P2 and front-panel I/O provides ROM-based
keyboard and mouse interface control. The front panel of the
MVME2603/2604 board has two 6-pin circular DIN connectors for the
keyboard and mouse connections.
PCI-ISA Bridge (PIB) Controller
The MVME2603/2604 uses a Winbond W83C553 bridge controller to
supply the interface between the PCI local bus and the ISA system I/O bus
(diagrammed in
Figure 1-1
in
Chapter 1, Hardware Preparation and
Installation
).