Print Engine Interface
MOTOROLA
MC68322 USER’S MANUAL
10-7
PBB—Page/Band Begin
This bit is posted at the start of every page or band. At the start of a page, PBB is set after
it receives FSYNC from the print engine and provides timing information to the software for
controlling the PVCCR’s PRT bit (typically, the timing of a print engine’s PRINT signal is
referenced to FSYNC). When starting a band in the middle of a page, a page/band begin
interrupt event is posted when the first page image data is read from memory.
PGE—Page End
This bit is issued at the bottom of every page (end-of-page is determined by the BND bit in
the PCB control field) immediately after the last word of the last scanline is read from
memory. In response to a page end interrupt event, the page or band buffer can be
reclaimed and reused for the next page.
BUD—Band Underrun
This bit indicates a banding error, which is posted when the last word of one band is read,
but the PCB register set (specifically, the page image bit address) for the next band is not
yet loaded. Band underruns usually point to a page description that is too complicated for
the given banding environment. This bit is only set when the BND bit in the PCB control field
is set, thus indicating that the image data is a band.
VUD—Video Underrun
This bit indicates that a video underrun has occurred. It is posted if the print engine requests
video data faster than the PVC can access memory. A video underrun is usually the result
of a band underrun or PVC error, but can also mean the memory configuration is too slow
for the video rate of the print engine.
ILA—Illegal Address
This bit indicates the PVC’s attempt to read from DRAM memory that is nonexistent because
of an out-of-range address. The out-of-range address occurs when reading page image
data and can be the result of loading an illegal memory address in the page image bit
address register or reading beyond the end of memory space. The PVC shuts down in
response to an out-of-range address. In this state, the PVC only responds to a PVC
soft-reset that is required to return the PVC to normal operation.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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