Allied Vision Technologies AVT Stingray Manual de instrucciones descargar pdf (Pagina 93)

Camera interfaces

STINGRAY Technical Manual V2.2.0

Pixel data

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.

• 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.

Field Description

data_length Number of bytes in the data field

tg Tag field

shall be set to zero

channel Isochronous channel number, as programmed in the iso_channel

field of the cam_sta_ctrl register

tCode Transaction code

shall be set to the isochronous data block packet tCode

sy 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

Video data payload Shall contain the digital video information

Table 31: Description of data block packet format

0-7 8-15 16-23 24-31

data_length tg channel tCode sy

header_CRC

Video data payload

data_CRC

Table 30: Isochronous data block packet format. Source: IIDC V1.31

sync bit

1 2 ... 88 89 90 91 92 93 94 95 96 97 98 ... 308 309

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Allied Vision Technologies AVT Stingray Manual de instrucciones Pagina 93