Datasheet

Glossary
MC9S12DP256 — Revision 1.1
Glossary
polarity — The two opposite logic levels, logic 1 and logic 0, which
correspond to two different voltage levels, V
DD
and V
SS
.
polling — Periodically reading a status bit to monitor the condition of a
peripheral device.
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 CPU. 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.
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
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