[sane-devel] GL848 reverse engineering

[Дмитрий Шелонин]

Hello

I'm analyzing data of communication between ambir ds687 on gl848 and a computer. 
Based on sources for gl847 and genesys_low and gl848 datasheet i can understand some sets of data. But there are also transfers of more then one or two bytes. 
I found values (when setting of register is perform) bites of which are not used (based on datasheet). Maybe it's not setting register?
Also for what high registers are? 
Why sometimes request 0x0c is used, but sometimes - 0x04? Can 0x04 be used to working with registers or only 0x0c?

for example
Here is out control transfer to 0 endpoint 
request = 0x04
value = 0x83
index = 0
length = 0x0c
data:
02 18 AE 00 AF 32 3D 00 3E 00 3F 64                                                                                                        . . ® . ¯ 2 = . > . ? d                                                                      

one another in transfer
1 bRequest 04h  
2 wValue 008Eh  
4 wIndex 3A22h  
6 wLength 0002h 
with data
00 55                                                                                                                                      . U