Configuration Basics
2-6
Am186™CC/CH/CU Microcontrollers User’s Manual
For example, if the segment register is loaded with 12A4h and the offset is 0022h, the
resultant address is 12A62h, as illustrated in Figure 2-3. To find the result:
1. The segment register contains 12A4h.
2. Shift the segment register left 4 places to produce 12A40h.
3. The offset is 0022h.
4. Add the shifted segment address (12A40h) to the offset (00022h). The result is 12A62h.
5. This address is placed on the pins of the microcontroller.
All instructions that address operands in memory must specify (implicitly or explicitly) a
16-bit segment value and a 16-bit offset value. The 16-bit segment values are contained in
one of the four internal segment registers (CS, DS, ES, and SS). For more information about
calculating the offset value, see “Addressing Modes” on page 2-9. For more information
about CS, DS, ES, and SS, see “Segments” on page 2-7.
In addition to 1 Mbyte of memory space, the Am186CC microcontroller provides 64K of I/O
space (see Figure 2-4). Note that the processor reserves 00000h to 003FFh in memory for
the interrupt vector table.
Figure 2-3
Physical Address Generation
2.4
I/O SPACE
The I/O space consists of 64K 8-bit or 32K 16-bit ports. The IN, INS, OUT, and OUTS
instructions address the I/O space with either an 8-bit port address specified in the
instruction, or a 16-bit port address in the DX register. Eight-bit port addresses are zero-
extended so that A15–A8 are Low. Note the processor reserves I/O port addresses 00F8h
through 00FFh. The microcontroller provides specific instructions for addressing I/O space.
1 2 A 4 0
0 0 0 2 2
1 2 A 6 2
1 2 A 4
0 0 2 2
Segment Base
Logical
Address
Shift
Left
4 Bits
Physical Address
To Memory
Offset
0
15
15
15
19
19
0
0
0
0
Содержание Am186 CC
Страница 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Страница 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Страница 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Страница 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Страница 39: ...Architectural Overview Am186 CC CH CU Microcontrollers User s Manual 1 15 Figure 1 6 32 Channel Linecard CH CC...
Страница 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Страница 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Страница 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Страница 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Страница 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...