Instruction manual

Marlin Technical ManualV.2.7.0

225

Configuration of the camera

GPDATA_BUFFER

GPDATA_BUFFER is a register that regulates the exchange of data between cam-

era and host for programming the LUT and the upload/download of the shading

image.

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 compared to

accessing every single quadlet.

• The big endian byte order of the 1394 bus is unlike the little endian byte

order of common operating systems (Intel PC). Each quadlet of the local

buffer, containing the LUT data or shading image for instance, has to be

swapped bytewise from little endian byte order to big endian byte order

before writing on the bus.

0xF1000FFC GPDATA_INFO --- [0..15] Reserved

BufferSize [16..31] Size of GPDATA_BUFFER

(byte)

0xF1001000

…

0xF10017FC

GPDATA_BUFFER

Table 130: Advanced register: GPData buffer

Note



• Read the BufferSize before using.

• GPDATA_BUFFER can be used by only one function at a

time.

Bit depth little endian  big endian Description

8 bit L0 L1 L2 L3  L3 L2 L1 L0 L: low byte

H: high byte

16 bit L0 H0 L1 H1  H1 L1 H0 L0

Table 131: Swapped first quadlet at address offset 0