Download M68ICS08SOM User`s Manual

P&E
Microcomputer
Systems, Inc.
accumulator), X (8-bit index register),
CCR (condition code register containing
the H, I, N, Z, and C bits), SP (stack
pointer), and PC (program counter).
Memory locations that hold status and
control information for on-chip
peripherals are called I/O and control
registers.
reset
Reset is used to force a computer system
to a known starting point and to force
on-chip peripherals to known starting
conditions.
APPENDIX B – GLOSSARY
—T—
—U—
—V—
VDD
The positive power supply to a
microcontroller (typically 5 volts dc).
VSS
The 0 volt dc power supply return for a
microcontroller.
—W—
—S—
S-record
A Motorola standard format used for
object code files.
Word
A group of binary bits. Some larger
computers consider a set of 16 bits to be a
word but this is not a universal standard.
simulator
A computer program that copies the
behavior of a real MCU.
—X—
X
source code
See source program
Abbreviation for index register, a CPU
register in the MC68HC908.
SP
—Y—
Abbreviation for stack pointer CPU
register in the MC68HC908 MCU.
source program
A text file containing instruction
mnemonics, labels, comments, and
assembler directives. The source file is
processed by an assembler to produce a
composite listing and an object file
representation of the program.
stack pointer
A CPU register that holds the address of
the next available storage location on the
stack.
M68ICS08SOM/D
—Z—
Z
Abbreviation for zero, a bit in the
condition code register of the
MC68HC908. A compare instruction
subtracts the contents of the tested value
from a register. If the values were equal,
the result of this subtraction would be 0 so
the Z bit would be set; after a load
accumulator instruction, the Z bit will be
set if the loaded value was $00.
B-5