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Display Line Boundary Conditions
4.8 Display Line Boundary Conditions
In order to simplify DMA transfers, FIFO doublewords do not contain data from
more than one display line. This means that a FIFO read must be performed
whenever 8-bytes have been output or when the line complete condition
(IPCOUNT = IMGHSIZE) occurs. Thus, every display line begins on a double-
word boundary and non-doubleword length lines are truncated at the end. An
example is shown in Figure 4–32.
In Figure 4–32 (8-bit Y/C mode), the line length is not a doubleword. When the
condition IPCOUNT = IMGHSIZE occurs, the remaining bytes of the FIFO
doubleword are ignored and the output switches to the default output value (or
the EAV code followed by blanking, if the end of the active video line has been
reached). The next display line then begins in the next FIFO location at byte 0.
This operation extends to all display modes.
SPRU629
Video Display Port
4-33
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