Texas Instruments TMS320C64x DSP - Manual (Page 171)

Raw Data Display Mode
Video Display Port 4-26 SPRU629
4.6.1 Raw Mode RGB Output Support
The raw data display mode has a special pixel count feature that allows the
FPCOUNT increment rate to be set. FPCOUNT increments only when INCPIX
samples have been sent out. This option allows proper tracking of the display
pixels when sending out sequential RGB samples. (INCPIX would be set to
three in this case, to indicate that a single pixel is represented by three output
samples.)
Sequential RGB samples output are also supported through a special FIFO
unpacking mode. When the 8-bit raw
¾
unpacking is selected (RGBX bit in
VDCTL), three output bytes are selected from each word and the fourth byte
is ignored. This allows the video port to correctly output data formatted as
24-bit RGB (or RGB
α
) words in memory.
4.6.2 Raw Data FIFO Unpacking
Display data is always packed into the FIFOs in 64-bit words and must be
unpacked before being sent to the display data pipeline. The unpacking and
byte ordering is dependant upon the display data size and the device endian
mode. For little-endian operation (default), data is unpacked from right to left;
for big-endian operation, data is unpacked from left to right.
The 8-bit raw mode uses a single data FIFO. Four samples are unpacked from
each word as shown in Figure 4–25.
Figure 4–25. 8-Bit Raw FIFO Unpacking
Raw FIFO
Raw 2 Raw 4 Raw 6 Raw 1 Raw 3 Raw 5 Raw 7 VDOUT[9–2]
VCLKOUT
63 5655 4847 4039 32
Raw 5 Raw 4 Raw 7 Raw 6
Raw 13 Raw 12 Raw 15 Raw 14
Little-Endian Unpacking
Raw 8 Raw 10 Raw 9 Raw 11 Raw 0
31 2423 1615 8 7 0
Raw 1 Raw 0 Raw 3 Raw 2
Raw 9 Raw 8 Raw 11 Raw 10
Raw FIFO
63 5655 4847 4039 32
Raw 5 Raw 4 Raw 7 Raw 6
Raw 13 Raw 12 Raw 15 Raw 14
Big-Endian Unpacking
31 2423 1615 8 7 0
Raw 1 Raw 0 Raw 3 Raw 2
Raw 9 Raw 8 Raw 11 Raw 10