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LCYC/CNT—Loop Cycles/Clock Count
This field is a special field that is used for two purposes. It is used as the LCYC field if the
LP bit is set to mark the beginning of a loop and it is used as a CNT field to count the number
of clocks to hold a line. CNT is assumed as 1 if the LCYC field is valid (LP = 1 and at
beginning of loop).
If LP = 0, then
CNT = the number of video clocks for this entry.
If LP = 1 and this is the beginning of the loop, then
LCYC = the number of loop cycles and CNT is already defined equal to 1.
If LP = 1 and this is the end of the loop, then
CNT = the number of video clocks for this entry.
Note: The value of the LCYC/CNT field must be
LP—Loop
This bit marks the beginning and end of a loop. The entry that marks the start of a loop must
have the LP bit and the LCYC field set to the number of desired iterations. The entry that
marks the end of a loop must have the LP bit set as well. Since only one bit marks the
beginning and end of a loop, nested loops are not possible.
LST—LAST
0 = This is not the last valid entry.
1 = This is the last valid entry.
19.5 PROGRAMMING EXAMPLES
The following examples demonstrate how to program the video controller to support an
NTSC or PAL interlaced display using Analog Devices ADV7176 video encoder with a few
assumptions.
• The CCIR 601 4:2:2 video data format is used.
• The ADV7176 is controlled by the HSYNC, BLANK, and FIELD signals (MODE1:slave
option) and has already been configured using I
• The image data resides in consecutive addresses of the memory.
MOTOROLA
≥
2
C.
MPC823e REFERENCE MANUAL
Video Controller
1 or erroneous operation will occur.
19-19
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