PNX1300/01/02/11 Data Book
Philips Semiconductors
7-2
PRELIMINARY SPECIFICATION
vided to synchronize message passing to other
PNX1300 message receivers.
7.4.1
Detailed Feature Descriptions
The EVO provides the following key functions.
Continuous digital video output of PAL or NTSC for-
mat data according to CCIR 601.
Transmission of YUV 4:2:2 co-sited pixel data across
a standard 8-bit parallel CCIR 656
1
interface.
Embedded SAV and EAV synchronization codes and
separate sync control signals compatible with Philips
DENC encoders are available.
Supports the nominal PAL/NTSC data rate of 27
MB/sec. (13. 5 Mpix/sec.), or any byte data rate up to
an 81-MHz EVO clock.
Custom video formats can be programmed with
frames or fields of up to 4095 lines of up to 4095 pix-
els, subject only to the data rate limitation above.
Support for video images in planar YUV 4:2:2 co-
sited, planar YUV 4:2:2 interspersed, or planar YUV
4:2:0 memory formats.
Optional 129-level alpha blending. Graphics overlay
image is in pixel-packed YUV 4:2:2+
α
format, and is
alpha blended on top of the video image. Each pixel
has a 1-bit alpha, which selects one of two global 8-
bit alpha values which provide 129 layers of transpar-
ency. With overlay enabled, the output byte data rate
is limited to 45% of the SDRAM clock, or up to an 81-
MHz EVO clock, whichever is smaller.
Optional horizontal 2X upscaling of the video image
for display. The overlay is always in display format.
In data-streaming mode, the EVO acts as a high
bandwidth continuous-output data channel. The byte
data rate is limited to an 81-MHz EVO clock.
In message-passing mode, the EVO can send mes-
sages from 1 word (4 bytes) up to 16 MB. The byte
data rate is limited to an 81-MHz EVO clock.
For diagnostic purposes, EVO output data can be
internally looped back to the VI port. This is con-
trolled by the VI DIAGMODE bit.
7.4.2
Summary of Operation
The EVO normally supplies continuous video data to its
outputs. The EVO is programmed and started by the
PNX1300 DSPCPU. The EVO issues an interrupt to the
DSPCPU at the end of each transmitted field, and/or at a
programmable vertical position in the field. The DSPCPU
updates the EVO video image data pointers with pointers
to the next field during the vertical blanking interval so as
to maintain continuous video output. During video output,
the EVO supplies embedded CCIR 656 SAV (Start Ac-
tive Video) and EAV (End Active Video) sync codes and
optionally supplies horizontal and frame sync signals.
The EVO can either supply pixel clock and horizontal and
frame timing signals or it can lock to external timing sig-
nals such as those supplied by a Philips SAA7125 DENC
digital encoder or similar sync source.
7.5
INTERFACE
Table 7-1
lists the interface pins of the EVO unit.
Figure 7-1
,
Figure 7-2
, and
Figure 7-3
illustrate typical
connections for commonly-used external devices that in-
terface to the EVO.
The most common way to generate analog video is
shown in
Figure 7-1
. In this setup, an SAA7125 Digital
Encoder (DENC) can be programmed to derive sync ei-
ther from the VO_DATA stream EAV/SAV codes, or from
its RCV1/2 pins.
Figure 7-2
illustrates how a byte-parallel ECL-level stan-
dard CCIR 656 interface can be created. In certain pro-
fessional applications, serial D1 video is also used. In
that case, the EVO can be connected to a Gennum
GS9022 Digital Video Serializer or similar part (not
shown).
Figure 7-3
shows the EVO unit of one PNX1300 con-
nected to the VI unit of a second PNX1300.
1.
Refer to CCIR recommendation 656: Interfaces for dig-
ital component video signals in 525 line and 625 line
television systems. Recommendation 656 is included in
the Philips Desktop Video Data Handbook.
PNX1300
VO_DATA[7:0]
(HS) VO_IO1
(FS) VO_IO2
VO_CLK
SAA7125
MP[7:0]
RCV1
RCV2
LLC
Figure 7-1. EVO connected to a digital video encod-
er (DENC).
PNX1300
VO_DATA[7:0]
VO_CLK
8
1
16
2
TTL to ECL
CCIR 656
Subminiature
“
D
”
Connector
Data A,B[7:0]
Clock A,B
Figure 7-2. EVO connected to a CCIR 656 video-
output connector.