Table of Contents
Paragraph
Number
3.1.4.3
3.1.4.4
3.1.4.5
3.1.5
3.1.6
3.1.7
3.1.7.1
3.1.7.2
3.1.7.3
3.1.7.4
3.2
3.2.1
3.2.1.1
3.2.1.2
3.2.2
3.2.2.1
3.2.2.2
3.2.2.3
3.2.3
3.2.4
3.2.5
3.2.5.1
3.2.5.2
3.2.5.3
3.2.5.4
3.2.6
3.3
3.3.1
3.3.2
3.3.2.1
3.3.2.2
3.3.3
3.4
3.5
3.5.1
3.5.2
3.5.2.1
3.5.2.2
3.5.2.3
3.5.2.4
3.5.2.5
3.5.2.6
3.5.2.6.1
3.5.2.6.2
3.5.3
Title
Page
Number
vi
MC68302 USER’S MANUAL
MOTOROLA
Address Sequencing..............................................................................3-10
Transfer Request Generation ................................................................3-11
Block Transfer Termination....................................................................3-12
IDMA Programming ...............................................................................3-13
DMA Bus Arbitration ..............................................................................3-14
Bus Exceptions......................................................................................3-14
Reset......................................................................................................3-15
Bus Error................................................................................................3-15
Halt.........................................................................................................3-15
Relinquish and Retry..............................................................................3-15
Interrupt Controller.................................................................................3-15
Overview................................................................................................3-16
IMP Interrupt Processing Overview .......................................................3-16
Interrupt Controller Overview.................................................................3-17
Interrupt Priorities...................................................................................3-18
INRQ and EXRQ Priority Levels............................................................3-18
INRQ Interrupt Source Priorities............................................................3-19
Nested Interrupts ...................................................................................3-19
Masking Interrupt Sources and Events..................................................3-20
Interrupt Vector......................................................................................3-21
Interrupt Controller Programming Model................................................3-24
Global Interrupt Mode Register (GIMR).................................................3-24
Interrupt Pending Register (IPR)............................................................3-26
Interrupt Mask Register (IMR)................................................................3-27
Interrupt In-Service Register (ISR).........................................................3-28
Interrupt Handler Examples...................................................................3-28
Parallel I/O Ports....................................................................................3-29
Port A.....................................................................................................3-29
Port B.....................................................................................................3-31
PB7–PB0 ...............................................................................................3-31
PB11–PB8 .............................................................................................3-32
I/O Port Registers ..................................................................................3-32
Dual-Port RAM.......................................................................................3-33
Timers....................................................................................................3-35
Timer Key Features ...............................................................................3-36
General Purpose Timer Units ................................................................3-37
Timer Mode Register (TMR1, TMR2) ....................................................3-37
Timer Reference Registers (TRR1, TRR2)............................................3-38
Timer Capture Registers (TCR1, TCR2)................................................3-39
Timer Counter (TCN1, TCN2)................................................................3-39
Timer Event Registers (TER1, TER2)....................................................3-39
General Purpose Timer Example...........................................................3-40
Timer Example 1....................................................................................3-40
Timer Example 2....................................................................................3-40
Timer 3 - Software Watchdog Timer......................................................3-41