CIP 3250A
ADVANCE INFORMATION
2.12.4. Orthogonal 4:1:1 Output Format
<23>AVHSTRT
<24>AVHLEN
The orthogonal 4:1:1 output format is compatible to the
industry standard. The U and V samples are skew cor-
rected and interpolated to an orthogonal sampling raster
(see Table 2–8).
AVO
start of field
<25>AVVSTRT
<26>AVVSTOP
Fig. 2–11: Programmable AVO signal
Table 2–8: 4:1:1 orthogonal output format
2
Select the desired mode via I C register <17>AVINT. If
the AVO signal is derived from the AVI signal, the I C
registers <22>AVDLY can be used to compensate inter-
nal processing delays of the CIP 3250A.
2
Luma
Chroma
Y
Y
Y
Y
4
1
2
3
7
6
5
4
3
2
1
C , C
U
U
U
U
U
U
U
U
3
7
6
5
4
1
1
7
6
1
1
5
4
1
1
3
2
1
0
2
C , C
2
1
I C register <22>AVPR can be used to precede the AVO
1
signal in relation to the RGB/YUV data output up to 3
clocks.
C , C
1
V
1
V
1
V
1
V
1
V
1
V
1
V
V
1
1
0
C , C
0
Y
Note: U x = pixel number and y = bit number
x
2.15. PRIO Interface
– real-time bus arbitration for 8 sources in DIGIT 3000
picture bus.
2.12.5. YUV Output Levels
Up to eight digital YUV or RGB sources (main decoder,
PIP, OSD, Text, etc.) may be selected in real-time by
means of a 3 bit priority bus. Thus, a pixelwise bus arbi-
tration and source switching is possible. It is essential
that all YUV-sources are synchronous and orthogonal.
The Y output black level of the CIP 3250A can be con-
verted from ITU-R 601 Standard (digital 16) to DIGIT
2000 Standard (digital 32) via I C register
2
<16>ADD16Q.
In general, each source (= master) has its own YUV bus
request. This bus request may either be software or
hardware controlled, i.e. a fast blank signal. Data colli-
sion is avoided by a bus arbiter that provides the individ-
ual bus acknowledge, in accordance to a user defined
priority.
2.13. I/O Code Levels
– ITU-R/DIGIT 3000 code levels:
Y or RGB = 16...240, clamp level = 16
UV = ±112, bias level = 0
– or DIGIT 2000 code levels:
Y = 32...127, clamp level = 32
UV = ±127, bias level = 0
Each master sends a bus request with its individual
priority ID onto the PRIO-bus and immediately reads
back the bus status. Only in case of positive arbitration
(send-PRIO-ID = read-PRIO-ID), the RGB/YUV outputs
become active and the data is send. PRIO requests
2
2.14. AVO Active Video Output
must be enabled by I C register <14>PRIOEN.
The requests asserted by the CIP 3250A may be gener-
ated by two different sources, which are selectable by
I C register <09>PRIOSRC. With the first source, the
CIP 3250A asserts requests only when the AVO signal
is active, else RGB/YUV outputs are tristated. With the
second source, the CIP 3250A asserts continuous re-
quests where the YUV data are forced to “clamp/bias
level data” (see section 2.13.) during the time that the
AVO signal is inactive.
In a DIGIT 3000 system environment, the AVO signal is
equivalent to the delayed AVI signal. It signalizes valid
video data and chroma multiplex at the output of the
CIP 3250A. Furthermore, the AVO signal can be used to
control the write enable of a frame memory. The polarity
2
2
of the AVO signal is programmable via I C register
<10>AVOINV.
In a DIGIT 2000 system environment, the AVO signal
2
can be programmed via I C registers <23> to <26> to
If only one source is connected to the YUV bus, the out-
puts GL, RC, and B may drive the bus during a full clock
define a window of valid video data at the output of the
CIP 3250A (see Fig. 2–11).
2
cycle. This can be selected by I C register <06>HALF-
OUT. If more than one source is connected to the YUV
bus, the output drivers must be switched to driving only
during the first half of clock cycle to avoid bus collision.
In the last case, the layout of the PCB must consider that
Micronas
15
MICRONAS [ MICRONAS ]
