MOTOROLA
iv
MC68331
USER’S MANUAL
TABLE OF CONTENTS
(Continued)
Title
Paragraph
Page
4.2.11
4.2.12
4.2.13
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
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
Periodic Interrupt Timer ..........................................................................4-7
Low-Power STOP Operation ..................................................................4-8
Freeze Operation ...................................................................................4-9
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