TABLE OF CONTENTS
(Continued)
Paragraph
Title
Page
4.2.11
4.2.12
4.2.13
Periodic Interrupt Timer ..........................................................................4-7
Low-Power STOP Operation ..................................................................4-8
Freeze Operation ...................................................................................4-9
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.4
4.4.1
4.4.1.1
4.4.1.2
4.4.1.3
4.4.1.4
4.4.1.5
4.4.1.6
4.4.1.7
4.4.1.8
4.4.1.9
4.4.1.10
4.4.1.11
4.4.2
4.4.3
4.4.4
4.4.5
4.5
4.5.1
4.5.2
4.5.2.1
4.5.2.2
4.5.3
System Clock .................................................................................................4-9
Clock Sources ......................................................................................4-10
Clock Synthesizer Operation ................................................................4-10
External Bus Clock ...............................................................................4-15
Low-Power Operation ...........................................................................4-15
Loss of Reference Signal .....................................................................4-16
External Bus Interface ..................................................................................4-17
Bus Signals ..........................................................................................4-18
Address Bus ................................................................................. 4-18
Address Strobe ............................................................................ 4-18
Data Bus ...................................................................................... 4-18
Data Strobe .................................................................................. 4-18
Read/Write Signal ........................................................................ 4-18
Size Signals ................................................................................. 4-18
Function Codes ............................................................................ 4-19
Data and Size Acknowledge Signals ........................................... 4-19
Bus Error Signal ........................................................................... 4-19
Halt Signal .................................................................................... 4-20
Autovector Signal ......................................................................... 4-20
Dynamic Bus Sizing .............................................................................4-20
Operand Alignment ..............................................................................4-21
Misaligned Operands ...........................................................................4-21
Operand Transfer Cases ......................................................................4-22
Bus Operation ..............................................................................................4-22
Synchronization to CLKOUT ................................................................4-23
Regular Bus Cycles ..............................................................................4-23
Read Cycle ................................................................................... 4-24
Write Cycle ................................................................................... 4-25
Fast Termination Cycles .......................................................................4-25
CPU Space Cycles ...............................................................................4-26
Breakpoint Acknowledge Cycle .................................................... 4-27
LPSTOP Broadcast Cycle ............................................................ 4-30
Bus Exception Control Cycles ..............................................................4-30
Bus Errors .................................................................................... 4-32
Double Bus Faults ........................................................................ 4-32
Retry Operation ............................................................................ 4-33
Halt Operation .............................................................................. 4-33
External Bus Arbitration ........................................................................4-34
4.5.4
4.5.4.1
4.5.4.2
4.5.5
4.5.5.1
4.5.5.2
4.5.5.3
4.5.5.4
4.5.6
MOTOROLA
iv
MC68331
USER’S MANUAL
MOTOROLA [ MOTOROLA ]
