1 (edited by jmc 2012-01-06 16:50:49)

Topic: LLCP workflow - how to receive data from target

Hi,

I am new on the forum.
I have some issues with LLCP understanding..

I already able communicate between 2 NFC devices. However, my code works only on one way.
I can push a message to the target but I can't succeed to receive one from target.

here my log file with big steps of LLCP

Send Symm
Initiator -> send Symm [9]: 74 06 0F 06 D4 06 00 00 00 
>>>| Symm, DSAP=0, SSAP=0
Received data which was send from the Target
Initiator -> received frame1[24] 17 17 D5 07 00 05 21 06 0F 63 6F 6D 2E 61 6E 64 72 6F 69 64 2E 6E 70 70 
<<<| Connect, DSAP=1, SSAP=33


Send a Connect to the Target
Initiator -> send Connect [26]: 74 17 0F 17 D4 06 01 05 21 06 0F 63 6F 6D 2E 61 6E 64 72 6F 69 64 2E 6E 70 70 
>>>| Connect, DSAP=1, SSAP=33
Received data which was send from the Target
Initiator -> received Connect response[11] 0A 0A D5 07 01 85 90 02 02 00 78
<<<| Cc, DSAP=33, SSAP=16


Send a Push to the Target
Initiator -> send Push [43]: 74 28 0F 28 D4 06 02 43 21 00 01 00 00 00 01 01 00 00 00 17 D1 01 13 54 02 65 6E 4E 44 45 46 20 50 75 73 68 20 53 61 6D 70 6C 65 
>>>| I, DSAP=16, SSAP=33
Received data which was send from the Target
Initiator -> received Push[8] 07 07 D5 07 02 87 50 01 
<<<| Rr, DSAP=33, SSAP=16
Pushed successfully

how to get my data from target???
Send receiveReady  or I ???
Initiator -> send RR [10]: 74 07 0F 07 D4 06 03 43 61 01 
>>>| Rr, DSAP=16, SSAP=33



Send a Disconnect to the Target
Initiator -> send Disconnect [9]: 74 06 0F 06 D4 06 04 41 61 
>>>| Disc, DSAP=16, SSAP=33

Could you explain me the LLCP workflow? the NFC forum documentation is not clear enough for me.

How can I receive the data from my target?
Do I have to send an I PDU ? to inverse the DSAP and SSAP? Do I have to fill the information parameter if yes with what information?
I have done some tests without success

Many thanks,
jmc

Re: LLCP workflow - how to receive data from target

Hello,

Have a look to libnfc-llcp WIP project :-)

Romuald Conty

Re: LLCP workflow - how to receive data from target

Hi there, I just joined the forum and I'm starting to learn NFC.

I have a ACS 122U reader and Nexus. I want to send data from Nexus to the reader. Is this libnfc-llcp the best choice for now?

Instead of that lib, which would be another options?

Thanks!: )