Table of Contents
Paragraph
Number
Title
Page
Number
MOTOROLA
MC68302 USER’S MANUAL
vii
3.5.3.1
3.5.3.2
3.5.3.3
3.6
3.6.1
3.6.2
3.6.2.1
3.6.2.2
3.6.3
3.7
3.8
3.8.1
3.8.2
3.8.3
3.8.4
3.8.5
3.8.5.1
3.8.5.2
3.8.6
3.8.7
3.8.7.1
3.8.7.2
3.8.7.2.1
3.8.7.2.2
3.8.7.2.3
3.9
3.9.1
3.10
3.10.1
3.10.2
3.10.3
3.10.4
3.10.5
3.10.6
Software Watchdog Timer Operation.................................................... 3-41
Software Watchdog Reference Register (WRR)................................... 3-41
Software Watchdog Counter (WCN)..................................................... 3-42
External Chip-Select Signals and Wait-State Logic .............................. 3-42
Chip-Select Logic Key Features............................................................ 3-45
Chip-Select Registers............................................................................ 3-45
Base Register (BR3–BR0) .................................................................... 3-45
Option Registers (OR3–OR0) ............................................................... 3-47
Chip Select Example............................................................................. 3-48
On-Chip Clock Generator...................................................................... 3-49
System Control...................................................................................... 3-50
System Control Register (SCR) ............................................................ 3-50
System Status Bits................................................................................ 3-51
System Control Bits............................................................................... 3-52
Disable CPU Logic (M68000)................................................................ 3-54
Bus Arbitration Logic............................................................................. 3-56
Internal Bus Arbitration.......................................................................... 3-56
External Bus Arbitration......................................................................... 3-58
Hardware Watchdog.............................................................................. 3-59
Reducing Power Consumption.............................................................. 3-60
Power-Saving Tips................................................................................ 3-60
Low-Power (Standby) Modes................................................................ 3-60
Low-Power Mode .................................................................................. 3-61
Lowest Power Mode.............................................................................. 3-62
Lowest Power Mode with External Clock.............................................. 3-62
Clock Control Register .......................................................................... 3-64
Freeze Control....................................................................................... 3-65
Dynamic Ram Refresh Controller.......................................................... 3-66
Hardware Setup .................................................................................... 3-66
DRAM Refresh Controller Bus Timing................................................... 3-67
Refresh Request Calculations............................................................... 3-67
Initialization............................................................................................ 3-68
DRAM Refresh Memory Map................................................................ 3-68
Programming Example.......................................................................... 3-69
Section 4
Communications Processor (CP)
Main Controller........................................................................................ 4-1
SDMA Channels...................................................................................... 4-3
Command Set ......................................................................................... 4-5
Command Execution Latency ................................................................. 4-7
Serial Channels Physical Interface.......................................................... 4-7
IDL Interface.......................................................................................... 4-11
GCI Interface......................................................................................... 4-14
PCM Highway Mode.............................................................................. 4-16
Nonmultiplexed Serial Interface (NMSI)................................................ 4-19
4.1
4.2
4.3
4.3.1
4.4
4.4.1
4.4.2
4.4.3
4.4.4