Apple Lisa - Overview of LISA Hardware; The Processor

Confidential
Lisa Hardware Reference Manual
HARDWARE OVERVIEW
The Lisa hardware can be divided into four functional pieces: the
CPU and memory management unit, the I/O circuitry, the memory arrays,
and the expansion slots. The main microprocessor is a Motorola
MC68000. It communicates with the rest of the Lisa world over two
buses: the system bus, and the memory bus. The I/O circuitry
includes the built-in parallel interface, two serial interfaces,
floppy disk controller, clock-calendar, speaker, and keyboard
interface.
SYSTEM BLOCK DIAGR&~
------- ---+
Expansion Slot a I
+--_._-,-----+
+---------- -I
+-----------+
I Expansion Slot 1 I
I Memory Array 1 I
+--------+
+------------+
I
+------ -=+
+-----------i-
I Expansion Slot 2
Memory Array 2 I
-- ... _------+
System Bus
Memory Bus
-------------- .. _--_ .. _--------------+
-+---
.--+
+---------
---_._---- .
I/O BOARD:
I I
CPU BOARD:
I I
Floppy Disk Controller
I
I
68000 and
Buffers
Hard Disk Interface
I
I
'
Memory Management Unit
7-Jul-81
-
+
1
I
(
I
Keyboard Interface
I I
Boot and diagnostics ROM
I
Speaker and CVSD
I I
Video Circuitry
I
Serial I/O Ports
I I
Memory Access Control
I
Clock/Calendar/Alarm
I I , I
+------
----+
+------------- ... =-----+
THE PROCESSOR
The Motorola MC68000 Microprocessor User's Manual fully describes the
operation of the processor, including its instruction set and timing.
The Lisa 68000 has a 5 megahertz clock. The memory cycle time is 800
nanoseconds; therefore instructions that use a multiple of four clock
cycles can execute without a wait state.
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