Gpdata_buffer, Little endian vs. big endian byte order, E chapter – ALLIED Vision Technologies Guppy PRO F-503 User Manual

Page 271: Table 150: advanced register: gpdata buffer

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Configuration of the camera

Guppy PRO Technical Manual V4.0.0

269

GPDATA_BUFFER

GPDATA_BUFFER is a general purpose register that regulates the exchange of
data between camera and host for:

writing look-up tables (LUTs) into the camera

uploading/downloading of shading image (not used) and defect pixel
correction data (only CMOS cameras)

GPDATA_INFO

Buffer size query

GPDATA_BUFFER

indicates the actual storage range

Little endian vs. big endian byte order

Read/WriteBlock accesses to GPDATA_BUFFER are recommended, to read
or write more than 4 byte data. This increases the transfer speed com-
pared to accessing every single quadlet.

The big endian byte order of the 1394 bus is unlike the little endian
byte order of common Intel PCs. Each quadlet of the local buffer,
containing the LUT data for instance, has to be swapped bytewise from
little endian byte order to big endian byte order before writing on the
bus.

Register

Name

Field

Bit

Description

0xF1000FFC GPDATA_INFO

BufferSize

[0..31]

Size of GPDATA_BUFFER
(byte)

Bit 0 ... bit 254 is reserved
for shading correction data
(not used)

Bit 255 is used for defect
pixel correction (only CMOS
cameras)

0xF1001000

0xF10017FC

GPDATA_BUFFER

Table 150: Advanced register: GPData buffer

Note

Read the BufferSize before using.

GPDATA_BUFFER can be used by only one function at a
time.

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