Configuration Basics
Am186™CC/CH/CU Microcontrollers User’s Manual
2-7
Figure 2-4
Memory and I/O Space
2.5
INSTRUCTION SET
The instruction set for the Am186CC/CH/CU microcontrollers is identical to the 80C186/188
instruction set. An instruction can reference from zero to several operands. An operand can
reside in a register, in the instruction itself, or in memory. Specific operand addressing
modes are discussed on page 2-9. For instruction set details, see the
Am186 and Am188
Family Instruction Set Manual, order #21267.
2.6
SEGMENTS
The microcontroller uses four segment registers:
1. Data Segment (DS): The processor assumes that all accesses to the program’s
variables are from the 64K space pointed to by the DS register. The data segment holds
data, operands, and so on.
2. Code Segment (CS): This 64K space is the default location for all instructions. All code
must be executed from the code segment.
3. Stack Segment (SS): The processor uses the SS register to perform operations that
involve the stack, such as pushes and pops. The stack segment provides temporary
storage space.
4. Extra Segment (ES): Typically, this segment supports large string operations and large
data structures. Certain string instructions assume the extra segment as the segment
portion of the address. By using a segment override, the extra segment can also support
a spare data segment.
When a data movement instruction does not define a segment, the processor assumes a
data segment. An instruction prefix can override the segment register. For speed and
compact instruction encoding, the addressing mode implies the segment register used for
physical address generation (see Table 2-4).
Memory
Space
1
I/O
Space
2
1 Mbyte
64 Kbyte
FFFFh
0000h
FFFFFh
00000h
Notes:
1. 00000h–003FFh are reserved for the interrupt vector table.
2. 00F8h–00FFh are reserved.
Summary of Contents for Am186 CC
Page 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Page 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Page 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Page 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Page 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Page 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Page 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Page 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Page 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...