Terasic HDMI-FMC, Руководство пользователя

Страница: 17 / 46

- 16 -
HDMI-FMC_User_Manual www.terasic.com
August 6, 2019
Notes
1. PR3:0 are cleared whenever TPI 0x1A[4] goes from 1 to 0.
2. The Input Clock (IDCK) and the TMDS Link Clock must be within the min/max range for the HDMI transmitter
for proper operation. Once the clocks go out of range, changing the field back to the correct value may not be
enough to recover. Proper recovery requires a switch into and out of power-down mode D2 (TPI 0x1E).
Input Bus Select. The input data bus can be either one pixel wide or one-half pixel wide. The bit defaults to 1 to
select full pixel mode. In one-half pixel mode, the full pixel is brought in on two successive clock edges (one rising,
one falling). Support is provided for 30- and 36-bit full-pixel and 15-, 18-, and 24-bit half-pixel input modes. The
corresponding color depth is selected at TPI 0x09[7:6].
Edge Select. Input data is latched on the selected rising or falling clock edge. For one-half pixel mode, this bit
indicates when it is 0 that data present at the falling edge is latched first, and when it is 1, data present at the rising
edge is latched first. The high-order bits are latched first.
TClkSel. If the video host drives in data using anything other than a 1:1 ratio of input clock speed to TMDS clock
speed, the host must program the clock multiplier logic.
◼
TPI AVI
Input and Output Format
I nput Format and Output Format are used by the host to specify the data format and range. At a reset
event, the chip defaults set input and output to be full-range RGB.
To set these registers, the host should read the EDID to determine whether the sink is DVI or HDMI,
and what its preferred output format is. Once written, the selection remains until overwritten or until
the next reset event.
Input Color Space / Output Format. These bits should be set as needed. The settings made to these
bits do not take effect until the AVI InfoFrame registers are programmed, so that any color space
change can be synchronized to the color settings specified in the InfoFrame (avoiding temporarily
green or pink images).
Range Compression. Range compression is enabled when RGB input and YCbCr output conversion
is selected.
Range Expansion. Range expansion is enabled when YCbCr input and RGB output conversion is
selected.