Pixel Data - AVT Pike Technical Manual

Camera interfaces

Pixel data

Field
data_length
tg
channel
tCode
sy
Video data payload
Pixel data are transmitted as isochronous data packets in accordance with
the 1394 interface described in IIDC V1.31. The first packet of a frame is
identified by the 1 in the sync bit (sy) of the packet header.
0-7
data_length
Table 30: Isochronous data block packet format. Source: IIDC V1.31
Description
Number of bytes in the data field
Tag field
shall be set to zero
Isochronous channel number, as programmed in the iso_channel
field of the cam_sta_ctrl register
Transaction code
shall be set to the isochronous data block packet tCode
Synchronization value (sync bit)
This is one single bit. It indicates the start of a new frame.
It shall be set to 0001h on the first isochronous data block of a frame,
and shall be set to zero on all other isochronous blocks
Shall contain the digital video information
Table 31: Description of data block packet format
• The video data for each pixel are output in either 8-bit or 14-bit format
(Packed 12-Bit Mode: 12-bit format).
• Each pixel has a range of 256 or 16384 (Packed 12-Bit Mode: 4096)
shades of gray.
• The digital value 0 is black and 255 or 16383 (Packed 12-Bit Mode:
4095) is white. In 16-bit mode the data output is MSB aligned.
8-15 16-23
tg channel
header_CRC
Video data payload
data_CRC
sync bit
24-31
tCode sy
PIKE Technical Manual V4.1.0
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