M68ICS08GR datasheet(402/408 Pages) FREESCALE

402 / 408 page

Glossary

Technical Data

MC68HC908GR8 — Rev 4.0

402

Glossary

MOTOROLA

prescaler — A circuit that generates an output signal related to the input signal by a fractional

scale factor such as 1/2, 1/8, 1/10 etc.

program — A set of computer instructions that cause a computer to perform a desired operation

or operations.

program counter (PC) — A 16-bit register in the CPU08. The PC register holds the address of

the next instruction or operand that the CPU will use.

pull — An instruction that copies into the accumulator the contents of a stack RAM location. The

stack RAM address is in the stack pointer.

pullup — A transistor in the output of a logic gate that connects the output to the logic 1 voltage

of the power supply.

pulse-width — The amount of time a signal is on as opposed to being in its off state.

pulse-width modulation (PWM) — Controlled variation (modulation) of the pulse width of a

signal with a constant frequency.

push — An instruction that copies the contents of the accumulator to the stack RAM. The stack

RAM address is in the stack pointer.

PWM period — The time required for one complete cycle of a PWM waveform.

RAM — Random access memory. All RAM locations can be read or written by the CPU. The

contents of a RAM memory location remain valid until the CPU writes a different value or

until power is turned off.

RC circuit — A circuit consisting of capacitors and resistors having a defined time constant.

read — To copy the contents of a memory location to the accumulator.

reserved memory location — A memory location that is used only in special factory test modes.

Writing to a reserved location has no effect. Reading a reserved location returns an

unpredictable value.

reset — To force a device to a known condition.

ROM — Read-only memory. A type of memory that can be read but cannot be changed (written).

The contents of ROM must be specified before manufacturing the MCU.

SCI — See "serial communication interface module (SCI)."

serial — Pertaining to sequential transmission over a single line.

Freescale Semiconductor, Inc.

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M68ICS08GR Datasheet(PDF) 402 Page - Freescale Semiconductor, Inc