MC68HC705J2 Datasheet, PDF (23/82 Pages) Freescale Semiconductor, Inc – member of the low-cost

Freescale Semiconductor, Inc.
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SECTION 4
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CENTRAL PROCESSOR UNIT
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This section describes the registers, aithmetic/logic unit (ALU), and low-power modes
of the M68HC05 central processor unit (CPU).
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4.1 CPU Registers
Figure 4-1 shows the five CPU registers. These are hard-wired registers within the
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CPU and are not part of the memory map.
7
7
0
A
ACCUMULATOR (A)
7
X
15
65
0000000011
SP
15
12 11*
87
0000
PCH
PCL
0
INDEX REGISTER (X)
0
STACK POINTER (SP)
0
PROGRAM COUNTER (PC)
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54
0
1 1 1H I N Z C
CONDITION CODE REGISTER (CCR)
CARRY/BORROW FLAG
ZERO PLAN
NEGATIVE FLAG
INTERRUPT MASK
HALF-CARRY FLAG
*Bit 11 of the program counter is fixed at 0 in MC68HC05J1 emulation mode.
Figure 4-1. Programming Model
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CENTRAL PROCESSOR UNIT
Rev. 2
4-1
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