Topic: llcp-snep discovery and connection cases
Hi, I am working on a school project to connect the pn532 with a nfc phone. I am using the seeedstudio nfc controller and the library they have, with some code that I am adding. My questions are related to the connection and discovery stage of the protocol.
Question 1: What to respond when the initiator make a request to the DSAP = 1 "discovery service".
Some phones(gs4, note 2):
- the phone send me 05 20 06 <SN> this is a CONNECT command to SAP =1 in the receiver device, then I respond with the CC command 81 84 2 2 0 78.
- then they send me an IPDU with the URI of the application in the foreground, I keep sending command as per the llcp-snep protocol in the nfc forum and everything finish cool.
"The problem is that I don't want the URI of the application in the foreground, I want the data of that application itself. "
- the phone send me 11 20 , this is a CONNECT command to SAP =4 in the receiver device, then I respond with the command CC 81 84 2 2 0 78.
- After this the phone send me the NDEF data as is suppose to be.
Now my question is: Why some times the phone send me the CONNECT command to the SAP =1 and some times to SAP =4. How would it be possible that the phone send me the request to the SAP = 4 every time so I could get the NDEF data in my app and not the URI of it,