Freescale Semiconductor, Inc.
Central Processor Unit (CPU)
3.3 CPU Registers
Figure 3-1 shows the five CPU registers. These are hard-wired registers
within the CPU and are not part of the memory map.
Bit 7
Bit 7
6
6
5
5
5
5
4
4
4
4
3
3
3
3
2
2
2
2
1
1
1
1
Bit 0
Bit 0
Bit 0
Bit 0
ACCUMULATOR (A)
INDEX REGISTER (X)
Bit 12 11 10
9
0
8
0
7
1
6
1
0
0
0
STACK POINTER (SP)
Bit 12 11 10
9
8
7
6
PROGRAM COUNTER (PC)
CONDITION CODE REGISTER (CCR)
Bit 7
1
6
1
5
1
4
3
I
2
1
Bit 0
C
H
N
Z
HALF-CARRY FLAG
INTERRUPT MASK
NEGATIVE FLAG
ZERO FLAG
CARRY/BORROW FLAG
Figure 3-1. Programming Model
Technical Data
44
MC68HC705C8A — Rev. 3
Central Processor Unit (CPU)
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