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

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.