Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
72 Central Processor Unit (CPU) MOTOROLA
Central Processor Unit (CPU)
6.3 Features
Features of the CPU08 include:
Fully upward, object-code compatibility with M68HC05 Family
16-bit stack pointer with stack manipulation instructions
16-bit index register with X-register manipulation instructions
8-MHz CPU internal bus frequency
64-Kbyte program/data memory space
16 addressing modes
Memory-to-memory data moves without using accumulator
Fast 8-bit by 8-bit multiply and 16-bit by 8-bit divide instructions
Enhanced binary-coded decimal (BCD) data handling
Modular architecture with expandable internal bus definition for
extension of addressing range beyond 64 Kbytes
Low-power wait mode
6.4 CPU Registers
Figure 6-1 shows the five CPU registers. CPU registers are not part of
the memory map.
Figure 6-1. CPU Registers
CARRY/BORROW FLAG
ZERO FLAG
NEGATIVE FLAG
INTERRUPT MASK
HALF-CARRY FLAG
TWO’S COMPLEMENT OVERFLOW FLAG
ACCUMULATOR (A)
INDEX REGISTER (H:X)
STACK POINTER (SP)
PROGRAM COUNTER (PC)
CONDITION CODE REGISTER (CCR)
V11HINZC
H X
0
0
0
0
7
15
15
15
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