AD9380 Datasheet, PDF (21/60 Pages) Analog Devices – Analog/HDMI Dual-Display Interface

AD9380
Color Space Conversion (CSC) Matrix
The CSC matrix in the AD9380 consists of three identical
processing channels. In each channel, three input values are
multiplied by three separate coefficients. Also included are an
offset value for each row of the matrix and a scaling multiple
for all values. Each value has a 13-bit, twos complement
resolution to ensure the signal integrity is maintained. The
CSC is designed to run at speeds up to 150 MHz, supporting
resolutions up to 1080p at 60 Hz. With any-to-any color space
support, formats such as RGB, YUV, YCbCr, and others are
supported by the CSC.
AUDIO PLL SETUP
Data contained in the audio infoframes, among other registers,
define for the AD9380 HDMI receiver not only the type of
audio, but the sample frequency. It also contains information
about the N and CTS values used to re-create the clock. With
this information, it is possible to regenerate the audio sampling
frequency. The audio clock is regenerated by dividing the 20-bit
CTS value into the TMDS clock, then multiplying by the 20-bit
N value. This yields a multiple of the sampling frequency (fS) of
either 128 × fS or 256 × fS. It is possible for this to be specified
up to 1024 × fS.
The main inputs, RIN, GIN, and BIN come from the 8- to 12-bit
inputs from each channel. These inputs are based on the input
format detailed in Table 11 The mapping of these inputs to the
CSC inputs is shown in Table 10.
128 × f_S
SOURCE DEVICE
DIVIDE
BY
N
CYCLE
TIME
COUNTER
CTS¹
SINK DEVICE
Table 10. CSC Port Mapping
Input Channel
R/CR
Gr/Y
B/CB
CSC Input Channel
RIN
GIN
BBIN
One of the three channels is represented in Figure 13. In each
processing channel, the three inputs are multiplied by three
separate coefficients marked a1, a2, and a3. These coefficients
are divided by 4096 to obtain nominal values ranging from
–0.9998 to +0.9998. The variable labeled a4 is used as an offset
control. The CSC_Mode setting is the same for all three
processing channels. This multiplies all coefficients and offsets
by a factor of 2 . ^CSC_Mode
VIDEO
CLOCK
N
REGISTER
N
TMDS
CLOCK
N¹
DIVIDE
BY
CTS
1_{N AND CTS VALUES ARE TRANSMITTED USING THE}
AUDIO CLOCK REGENERATION PACKET. VIDEO
CLOCK IS TRANSMITTED ON TMDS CLOCK CHANNEL.
MULTIPLY 128 × f_S
BY
N
Figure 14. N and CTS for Audio Clock
AUDIO BOARD LEVEL MUTING
The audio can be muted through the infoframes or locally
via the serial bus registers. Muting can be controlled with
Register R0x57, Bits [7:4].
AVI Infoframes
The functional diagram for a single channel of the CSC, as
shown in Figure 13, is repeated for the remaining G and B
channels. The coefficients for these channels are b1, b2, b3, b4,
c1, c2, c3, and c4.
a1[12:0]
R_IN [11:0]
×
×
1
4096
+
a2[12:0]
B_IN [11:0]
×
a3[12:0]
×
1
4096
a4[12:0]
+
+
CSC_Mode[1:0]
×4
2
R_OUT [11:0]
×2
1
0
G_IN [11:0]
×
×
1
4096
Figure 13. Single CSC Channel
A programming example and register settings for several
common conversions are listed in the Color Space Converter
(CSC) Common Settings section.
For a detailed functional description and more programming
examples, refer to Application Note AN-795, AD9880 Color
Space Converter User's Guide.
The HDMI TMDS transmission contains infoframes with
specific information for the monitor such as:
• Audio information
o 2 to 8 channels of audio identified
o Audio coding
o Audio sampling frequency
• Speaker placement
• N and CTS values (for reconstruction of the audio)
• Muting
• Source information
o CD
o SACD
o DVD
• Video information
o Video ID Code (per CEA861B)
o Color space
o Aspect ratio
o Horizontal and vertical bar information
o MPEG frame information (I, B, or P frame)
• Vendor (transmitter source) name and product model
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