mc68hc08qa24 Freescale Semiconductor, Inc, mc68hc08qa24 Datasheet - Page 85

• Manufacturer Part Number: mc68hc08qa24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

7.4.1 Accumulator
7.4.2 Index Register
MC68HC08QA24
Freescale Semiconductor
Reset:
Read:
Write:
Reset:
Read:
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
12
0
Figure 7-3. Index Register (H:X)
Figure 7-2. Accumulator (A)
11
0
5
10
0
9
0
Unaffected by reset
4
8
0
X
7
3
X
6
Central Processor Unit (CPU)
5
X
2
X
4
X
3
1
Technical Data
X
2
X
1
Bit 0
Bit
0
X
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