MC68HC05JJ6 Datasheet, PDF (40/216 Pages) Freescale Semiconductor, Inc – General Release Specification Microcontrollers

Central Processor Unit (CPU)
3.2 Introduction
This section describes the CPU registers. Figure 3-1 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
111
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 3-1. 68HC05 Programming Model
3.3 Accumulator
The accumulator is a general-purpose 8-bit register as shown in Figure
3-2. The CPU uses the accumulator to hold operands and results of
arithmetic and non-arithmetic operations.
Bit 7
Read:
Write:
Reset:
6
5
4
3
2
Unaffected by Reset
Figure 3-2. Accumulator (A)
1
Bit 0
General Release Specification
40
MC68HC05JJ6/MC68HC05JP6 — Rev. 3.2
Central Processor Unit (CPU)
Freescale Semiconductor