MC912DG128A Motorola, MC912DG128A Datasheet - Page 397

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

program — A set of computer instructions that cause a computer to perform a desired operation
program counter (PC) — A 16-bit register in the CPU. The PC register holds the address of the
pull — An instruction that copies into the accumulator the contents of a stack RAM location. The
pullup — A transistor in the output of a logic gate that connects the output to the logic 1 voltage
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
push — An instruction that copies the contents of the accumulator to the stack RAM. The stack
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
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.
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).
MOTOROLA
or operations.
next instruction or operand that the CPU will use.
stack RAM address is in the stack pointer.
of the power supply.
signal with a constant frequency.
RAM address is in the stack pointer.
contents of a RAM memory location remain valid until the CPU writes a different value or
until power is turned off.
Writing to a reserved location has no effect. Reading a reserved location returns an
unpredictable value.
The contents of ROM must be specified before manufacturing the MCU.
Glossary
MC68HC912DT128A Rev 1.0
Glossary
397