SECTION
1.
SYSTEM BOARD
Contents
Description
1-3
Microprocessor
....................••...........••
1-3
Data Flow Diagrams
••••........•.....•............
1-5
System Memory Map
.......•...........•..........
1-8
System Timers
........................•..........
1-11
System Interrupts
•.•............••..••.......••..
1-11
ROM
..............................•..........
1-13
RAM
..•••.••..........•.••••...•....••.••.•...
1-13
DMA
..........................................
1-13
110
Channel
...•.••.............••.••..........•
1-14
System Board Diagram
......•.•...........•.......
1-16
1/0 Channel Diagram
•.•.........•••••.........•.•
1-18
I/O
Channel Description
..........••...•.........••
1-20
110
Address Map
................................
1-24
Other Circuits
...................................
1-
25
Speaker Circuit
...............................
1-25
Cassette Interface
.............................
1-27
Cassette Circuit Block Diagrams
..................
1-28
8255A
I/O
Bit Map
...........................
1-31
System-Board Switch Settings
....................
1-33
System Board
1-1