MC68HC908KX2 MOTOROLA [Motorola, Inc], MC68HC908KX2 Datasheet - Page 61

• Manufacturer Part Number: MC68HC908KX2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

5.4.1 Accumulator
5.4.2 Index Register
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
MOTOROLA
Reset:
Reset:
Read:
Read:
Write:
Write:
The accumulator (A) is a general-purpose 8-bit register. The CPU uses
the accumulator to hold operands and the results of arithmetic/logic
operations.
The 16-bit index register (H:X) allows indexed addressing of a 64-Kbyte
memory space. H is the upper byte of the index register, and X is the
lower byte. H:X is the concatenated 16-bit index register.
In the indexed addressing modes, the CPU uses the contents of the
index register to determine the conditional address of the operand.
The index register can serve also as a temporary data storage location.
X = Indeterminate
Bit
15
0
Bit 7
14
0
Central Processor Unit (CPU)
13
0
6
Figure 5-3. Index Register (H:X)
12
0
Figure 5-2. Accumulator (A)
11
0
5
10
0
Unaffected by reset
9
0
4
8
0
X
7
3
X
6
Central Processor Unit (CPU)
5
X
2
X
4
X
3
1
Technical Data
CPU Registers
X
2
X
1
Bit 0
Bit
X
0
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