M68ICS08MR Datasheet, PDF (90/100 Pages) Motorola, Inc – In-Circuit Simulator

Glossary
User’s Manual
90
clock — A square wave signal that is used to sequence events in a computer.
command set — The command set of a CPU is the set of all operations that
the CPU knows how to perform. One way to represent an instruction set
is with a set of shorthand mnemonics such as LDA meaning load A.
Another representation of an instruction set is the opcodes that are
recognized by the CPU.
CPU — Central processor unit. The part of a computer that controls execution
of instructions.
CPU cycles — A CPU clock cycle is one period of the internal bus-rate clock.
Normally, this clock is derived by dividing a crystal oscillator source by
two or more so the high and low times will be equal. The length of time
required to execute an instruction is measured in CPU clock cycles.
CPU registers — Memory locations that are wired directly into the CPU logic
instead of being part of the addressable memory map. The CPU always
has direct access to the information in these registers. The CPU
registers in an MC68HC908 are A (8-bit 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).
cycles — See CPU cycles.
data bus — A set of conductors that are used to convey binary information
from a CPU to a memory location or from a memory location to a CPU;
in the HC08, the data bus is 8-bits.
development tools — Software or hardware devices used to develop computer
programs and application hardware. Examples of software
development tools include text editors, assemblers, debug monitors,
and simulators. Examples of hardware development tools include
simulators, logic analyzers, and PROM programmers. An in-circuit
simulator combines a software simulator with various hardware
interfaces.
DIP — Dual in-line package.
DTR — Data transfer request.
EPROM — Erasable, programmable read-only memory. A non-volatile type
Glossary
M68ICS08MR In-Circuit Simulator
MOTOROLA