MC68HC705J1A

Manufacturer Part NumberMC68HC705J1A
ManufacturerMotorola
MC68HC705J1A datasheet
 


Specifications of MC68HC705J1A

CaseDIP-20L  
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Page 48/162:

CPU Registers

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Central Processor Unit (CPU)
3.5 CPU Registers
The M68HC05 CPU contains five registers that control and monitor
microcontroller unit (MCU) operation:
CPU registers are not memory mapped.
3.5.1 Accumulator
The accumulator (A) is a general-purpose 8-bit register. The CPU uses
the accumulator to hold operands and results of ALU operations.
Read:
Write:
Reset:
3.5.2 Index Register
In the indexed addressing (X) modes, the CPU uses the byte in the index
register to determine the conditional address of the operand. The index
register also can serve as a temporary storage location or a counter.
Read:
Write:
Reset:
Technical Data
48
Accumulator
Index register
Stack pointer
Program counter
Condition code register
Bit 7
6
5
4
Unaffected by reset
Figure 3-2. Accumulator (A)
Bit 7
6
5
4
Unaffected by reset
Figure 3-3. Index Register (X)
Central Processor Unit (CPU)
3
2
1
Bit 0
3
2
1
Bit 0
MC68HC705J1A — Rev. 4.0
MOTOROLA