Real Address Mode
In real mode the 386SX microprocessor operates as a very fast 8086,
but with a 32-bit extension if desired. Real mode is required primarily
to set up the processor for protected mode operation.
The segmentation unit shifts the selector left four bits and adds the
result to the effective address to form the linear address. This linear
address is limited to 1 megabyte. In addition, real mode has no paging
capability.
System Timers
The system has three programmable timer/counters controlled by the
Intel 8254-2 chip. These are channels 0 through 2 defined as follows:
Table 6 -1: Channel 0
Table 6-2: Channel 1
NOTE: Channel 1 is programmed to generate a 15 microsecond
signal.
Table 6-3: Channel 2
18
Chapter 6: Appendix
Содержание Apex 386SX/20
Страница 1: ...PEER 2030 2 O M H z 3 8 6 S X S Y S T E M U ser s Manual ...
Страница 15: ...Chapter 1 System Overview ...
Страница 38: ...Chapter 2 Setting Up Your System ...
Страница 43: ...Figure 2 2 The Location of W9 80386SX and 80387SX Chapter 2 Setting Up Your System 5 ...
Страница 48: ...Figure 2 6 512KB Total Onboard System Memory 10 Chapter 2 Setting Up Your System ...
Страница 49: ...Figure 2 7 640 KB Total Onboard System Memory Chapter 2 Setting Up Your System 11 ...
Страница 50: ...Figure 2 8 1 MB Total Onboard System Memory 12 Chapter 2 Setting Up Your System ...
Страница 51: ...Figure 2 9 1 5 MB Total Onboard System Memory Chapter 2 Setting Up Your System 13 ...
Страница 52: ...Figure 2 11 2MB Total Onboard System Memory B 14 Chapter 2 Setting Up Your System ...
Страница 53: ...Figure 2 12 3MB Total Onboard System Memory Chapter 2 Setting Up Your System 15 ...
Страница 54: ...Figure 2 13 4MB Total Onboard System Memory 16 Chapter 2 Setting Up Your System ...
Страница 55: ...Figure 2 14 5MB Total Onboard System Memory Chapter 2 Setting Up Your System 17 ...
Страница 61: ...Chapter 3 Operating Your System ...
Страница 80: ...Chapter 4 Keyboard ...
Страница 90: ...Chapter 5 Troubleshooting ...
Страница 98: ...Appendix ...
Страница 102: ...Figure 6 3 Connecting a Floppy Disk Drive Figure 6 4 Connecting a Floppy Disk Drive to an FDC Card 4 Chapter 6 Appendix ...
Страница 103: ...Figure 6 5 Connecting a Hard Disk Drive Figure 6 6 Connecting a Hard Disk Drive to an HOC Card Chapter 6 Appendix 5 ...
Страница 123: ...Chapter 7 Glossary ...