MC68HC708MP16 Datasheet, PDF (386/398 Pages) Freescale Semiconductor, Inc – Microcontrollers

Glossary
Technical Data
386
CPU08 — The central processor unit of the M68HC08 Family.
CPU cycles — A CPU clock cycle is one period of the internal bus-rate
clock, f_OP, normally 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 M68HC08 are:
• A (8-bit accumulator)
• H:X (16-bit index register)
• SP (16-bit stack pointer)
• PC (16-bit program counter)
• CCR (condition code register containing the V, H, I, N, Z, and C
bits)
CSIC — customer-specified integrated circuit
cycle time — The period of the operating frequency: t_CYC = 1/f_OP.
decimal number system — Base 10 numbering system that uses the
digits zero through nine.
direct memory access module (DMA) — A M68HC08 Family module
that can perform data transfers between any two CPU-addressable
locations without CPU intervention. For transmitting or receiving
blocks of data to or from peripherals, DMA transfers are faster and
more code-efficient than CPU interrupts.
DMA — See direct memory access module (DMA).
DMA service request — A signal from a peripheral to the DMA module
that enables the DMA module to transfer data.
duty cycle — A ratio of the amount of time the signal is on versus the
time it is off. Duty cycle is usually represented by a percentage.
Glossary
MC68HC708MP16 — Rev. 3.1
Freescale Semiconductor