Motorola MC68HC05T16 Technical Data Manual page 80

9
that could have been displayed, the OSD is so designed that these remaining lines will not be
displayed. The same result applies to the complete overlap situation with different character sizes.
A row display is terminated if:
1) the part of the row display which is not overridden by other overlapping rows
has been completed, or
2) it completely overlaps a row or rows with higher priority, or
3) the part of the row display which does not overlap vertical retrace period has
been completed. (This applies to rows immediately before vertical retrace)
Note that the judgement of overlap is totally based on the vertical position of rows, it has nothing
to do with character size of rows. RiCF bit of Frame Control 3 and Status register will also be set
when a row display is terminated.
MOTOROLA
9-10
Background
R, G, B, or I
Char
R, G, B, or I
R, G, B, or I
FBKG
HTONE
RiBE=0, BGEN=0, FBKGCi=X
Figure 9-4 Output Signal Timing Diagram - Without Background
ON-SCREEN DISPLAY
Timing signals for 5th line (line 4)
RiBE=1, SHDW=0, BGEN=0, FGKGCi=X
TPG
MC68HC05T16