MC68HC705E5 Datasheet, PDF (30/148 Pages) Freescale Semiconductor, Inc – General Release Specification

Freescale Semiconductor, Inc.
Central Processing Unit (CPU)
7
0 _STACK
INCREASING
MEMORY
ADDRESSES
1 1 1 CONDITION CODE REGISTER _I
R
E
T
U
R
N
ACCUMULATOR
INDEX REGISTER
PCH
N
T
E DECREASING
R
MEMORY
R ADDRESSES
U
P
PCL
T
UNSTACK
NOTE: Since the stack pointer decrements during pushes, the PCL is stacked
first, followed by PCH, etc. Pulling from the stack is in the reverse
Figure 3-2. Stacking Order
3.3 Accumulator
The accumulator is a general-purpose 8-bit register used to hold
operands and results of arithmetic calculations or data manipulations.
Bit 7 6
5
4
3
2
1 Bit 0
A
Figure 3-3. Accumulator (A)
3.4 Index Register
The index register is an 8-bit register used for the indexed addressing
value to create an effective address. The index register may also be
used as a temporary storage area.
Bit 7 6
5
4
3
2
1 Bit 0
X
Figure 3-4. Index Register (X)
General Release Specification
Central Processing Unit (CPU)
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MC68HC705E5 — Rev. 1.0