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Glossary
VBP
Vertical Back Porch. The VBP, whose name is derived from the shape of the signal in the
time domain, is the delay between the vertical synchronization signal indexes to a new
pixel data frame, and when the actual pixel data is sent to the LCD driver.
VIC
Vectored Interrupt Controller. The VIC hardware sorts and prioritizes interrupts, allowing
interrupts to cause automatic routing (vectoring) of the software to unique interrupt service
routines (ISR). This allows faster interrupt servicing than requiring software to determine
the interrupting source prior to entering the proper ISR. The VIC also allows prioritizing
interrupts such that a higher priority interrupt can interrupt a lower priority ISR.
VFP
Vertical Front Porch. The VFP, whose name is derived from the shape of the signal in the
time domain, is the delay between the actual pixel data sent to the LCD driver, and the ver-
tical synchronization signal indexes.
Volatile Memory
A general term for any memory technology that loses its contents when power is removed.
Examples are RAM, SRAM and SDRAM. See Non-Volatile Memory.
VSW
Vertical Synchronization Pulse Width. The quantity of vertical synchronization lines fed to
an LCD panel.
W
In register tables, Write-Only. Write Only fields should not be read as the data is invalid.
WDT
Watchdog Timer. The WDT can be programmed to reset the SoC if it is not periodically
serviced by software. This allows for a 'sanity check', which can prevent error conditions
from locking up the SoC. If the WDT is not serviced within the programmed time, it is
assumed that a non-recoverable error has occurred and the system must be reset to clear
the error. The LH75400/01/10/11 WDT can be programmed to issue a reset upon timeout,
or an interrupt. The interrupt condition allows an ISR to attempt to resolve the error prior
to a system reset. In this mode, a second consecutive timeout of the WDT results in a sys-
tem reset.
Word
In the context of 32-bit SoCs, a word is an ordered set of four bytes, totaling 32-bits. Words
are always shown with the MSB at the left and the LSB on the right.
27-6
LH75400/01/10/11 (Preliminary) User's Guide
7/15/03
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