[Bluez-devel] Re: hcidump iconsistent byte ordering?

[soraberri <421246@posta.unizar.es>]

Hi Marcel,

Ok, the opcode is encoded in two fields:
OGF Range (6 bits): 0x00-0x3F
OCF Range (10 bits): 0x0000-0x03FF

and hcidump writes these two fields (0x01|0x0001) for the inquiry 
command, which in binary form it is

	0000 0100 0000 0001

and corresponds to 0x0401, which is shown as 01 04 by hcidump...

all rigth, I was thinking of 0x01 as 8 bits instead of 6.

thanks Marcel!

Regards

Luis Peiro


Marcel Holtmann wrote:
> Hi Luis,
> 
> 
>>let's say I want to decipher the first two HCI events from the "hcitool 
>>inq" dump:
>>< HCI Command: Inquiry (0x01|0x0001) plen 5
>>   33 8B 9E 08 64
>> > HCI Event: Command Status (0x0f) plen 4
>>   00 01 01 04
>>
>>Easily, the first one is the Inquiry command. Its command parameters are 
>>specified (Bluetooth Specification 1.1) in this order: LAP, 
>>Inquiry_Length, Num_Responses; so from the hcidump output we have:
>>
>>	LAP: 0x9E8B33 (general inquiry LAP)
>>	Inquiry_Length: 0x08
>>	Num_Responses: 0x64
>>
>>so far so good; it makes sense, but how about the command status event? 
>>the order of its event parameters from the specification is: Status, 
>>Num_HCI_Command_Packets, Command_Opcode. So following the same procedure 
>>  as before I would get:
>>	
>>	Status: 0x00
>>	Num_HCI_Command_Packets: 0x01
>>	Command_Opcode: 0x0401
>>
>>but this doesn't make sense because Command_Opcode should be 0x0001 
>>(Inquiry command). These bytes are now located as the two first bytes of 
>>the output, and the reading order is different from that of LAP's order 
>>in the Inquiry Command.
>>
>>So, I'm asking, how must I read hcidump output in order to agree with 
>>the specification?
> 
> 
> the command opcode consists of OGF and OCF. Look at the specification on
> how to encode them into the command opcode.
> 
> Regards
> 
> Marcel
> 
> 
> 
> 
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