CY8C20X34_08 Datasheet, PDF (202/216 Pages) Cypress Semiconductor – Technical Reference Manual (TRM)

Section F: Glossary
interrupt
A suspension of a process, such as the execution of a computer program, caused by an event
external to that process and performed in such a way that the process can be resumed.
interrupt service rou-
tine (ISR)
A block of code that normal code execution is diverted to when the M8C receives a hardware
interrupt. Many interrupt sources may each exist with its own priority and individual ISR code
block. Each ISR code block ends with the RETI instruction, returning the device to the point in
the program where it left normal program execution.
J
jitter
1. A misplacement of the timing of a transition from its ideal position. A typical form of corruption
that occurs on serial data streams.
2. The abrupt and unwanted variations of one or more signal characteristics, such as the inter-
val between successive pulses, the amplitude of successive cycles, or the frequency or
phase of successive cycles.
K
keeper
A circuit that holds a signal to the last driven value, even when the signal becomes un-driven.
L
latency
The time or delay that it takes for a signal to pass through a given circuit or network.
least significant bit
(LSb)
The binary digit, or bit, in a binary number that represents the least significant value (typically the
right-hand bit). The bit versus byte distinction is made by using a lower case “b” for bit in LSb.
least significant byte
(LSB)
The byte in a multi-byte word that represents the least significant value (typically the right-hand
byte). The byte versus bit distinction is made by using an upper case “B” for byte in LSB.
Linear Feedback Shift A shift register whose data input is generated as an XOR of two or more elements in the register
Register (LFSR)
chain.
load
The electrical demand of a process expressed as power (watts), current (amps), or resistance
(ohms).
logic function
A mathematical function that performs a digital operation on digital data and returns a digital
value.
look-up table (LUT)
A logic block that implements several logic functions. The logic function is selected by means of
select lines and is applied to the inputs of the block. For example: A 2 input LUT with 4 select
lines can be used to perform any one of 16 logic functions on the two inputs resulting in a single
logic output. The LUT is a combinational device; therefore, the input/output relationship is contin-
uous, that is, not sampled.
low time
The amount of time the signal has a value of ‘0’ in one period, for a periodic digital signal.
low voltage detect
(LVD)
A circuit that senses Vdd and provides an interrupt to the system when Vdd falls below a
selected threshold.
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Spec. # 001-13033 Rev. *A, February 19, 2008
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