MC68HC11P2 Datasheet, PDF (262/268 Pages) Motorola, Inc – Microcontrollers

Glossary
Freescale Semiconductor, Inc.
port — A set of wires for communicating with off-chip devices.
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.
register — A circuit that stores a group of bits.
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.
Technical Data
Glossary
For More Information On This Product,
Go to: www.freescale.com
MC68HC11P2 — Rev 1.0