MC68HC05X4 Datasheet, PDF (28/156 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
CPU
Introduction
This chapter describes the CPU registers and the HC05 instruction set.
CPU Registers
Figure 1 shows the five CPU registers. CPU registers are not part of the
memory map.
7
0
A
ACCUMULATOR (A)
7
0
X
INDEX REGISTER (X)
15
65
0
0000000011
SP
STACK POINTER (SP)
15
10
87
0
PCH
PCL
PROGRAM COUNTER (PC)
7
54
0
1 1 1 H I N Z C CONDITION CODE REGISTER (CCR)
HALF-CARRY FLAG
INTERRUPT MASK
NEGATIVE FLAG
ZERO FLAG
CARRY/BORROW FLAG
Figure 1. Programming Model
Accumulator
The accumulator is a general-purpose 8-bit register. The CPU uses the
accumulator to hold operands and results of arithmetic and
non-arithmetic operations.
MC68HC05X4
28
CPU
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