Motorola MVME2603-1121A, Installation And Use Manual

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Block Diagram
3-12
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 ).