Zilog EZ80F916 - Manual (Page 398)

eZ80
®
CPU
User Manual
UM007715-0415 Glossary
389
MSB.
Most Significant Byte.
multiplexing (MUXing).
The combining of two or more information channels onto a common
transmission medium. In electrical communications, the two basic forms of multiplexing are time-division
multiplexing (TDM) and frequency-division multiplexing (FDM).
MUX.
Multiplexer.
N.
See Add/Subtract Flag.
NACK.
See Negative Acknowledge Character.
NC.
No Carry Flag.
DJNZ.
Decrement and Jump if Not Zero.
NEG.
Negate Accumulator; an arithmetic instruction.
Negative-Acknowledge Character (NACK).
A transmission control character sent by a station as a
negative response to the station with which the connection has been set up. In binary synchronous
communication protocol, the NAK is used to indicate that an error was detected in the previously received
block and that the receiver is ready to accept retransmission of that block.
NMI.
Nonmaskable interrupt.
Nonmaskable Interrupt.
Nonmaskable interrupts are always enabled. The eZ80
®
CPU will always
respond to a nonmaskable interrupt service request from an external device or on-chip peripheral. A
nonmaskable interrupt cannot be disabled by the programmer. See maskable interrupt.
NOP.
An acronym for No Operation, an instruction whose sole function is to increment the program
counter, but that does not affect any changes to registers or memory.
NORMAL mode.
Mode of operation without error correction active.
NRZ.
NonReturn to Zero.
NRZI.
NonReturn to Zero Inverted.
OE.
Output Enable.
Opcode.
Operation Code, a quantity that is altered by a microcontroller’s instruction.
Opcode suffix.
Opcode suffixes are additions to an instruction set that assist with memory mode
switching operations. These suffixes are appended to many instructions to indicate that a memory mode
change or an exception to a standard memory mode operation is being requested. There are 4 individual
suffixes available for use on the eZ80 ® : .SIS, .SIL, .LIS, and .LIL.
Open-Drain.
Operand.
The data unit that is operated on; usually identified by an address in an instruction. For example,
in "add 100 to 400", 100 and 400 are operands.
OR.
Logical OR; a logical instruction.
OTDM (OTDMR).
Output to I/O and Decrement (with Repeat); an input/output instruction.
OTIM (OTIMR).
Output to I/O and Increment (with Repeat); an input/output instruction.
OUT.
Output to I/O; an input/output instruction.
OUTD (OTDR).
Output to I/O and Decrement (with Repeat); an input/output instruction.
OUTD2 (OTD2R).
Output to I/O and Decrement (with Repeat); an input/output instruction.