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don / NDEF

NDEF Library for Arduino. Read and Write NDEF Messages to NFC tags with Arduino.
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P2P_Sending limitation #32

Closed lorant124 closed 6 years ago

lorant124 commented 8 years ago

Hi Don,

I would like to ask for help, I m currently using your library of NFC to send messages to android over p2p protocol. I would like to send at least 2000 characters.

Is It possible or it is given by the hardrware PN532, I use ESP8266 and now I'm able to send 223 byte. I know that the library limites the number of bytes "SNEP packet, the packet should be less than (255 - 2 - 3) bytes". My question is if it was possible to send over this limit?

Thank you very much for your answear and your help,

Lorant

don commented 8 years ago

The NDEF library can encode messages of 2000 characters. Unfortunately it looks like the SNEP write function in PN532 is limited to 250 bytes https://github.com/Seeed-Studio/PN532/blob/master/PN532/snep.h#L23

I don't know why this limit exists and if it can be changed. I've emailed @xiongyihui to see if he has more info. Maybe large messages need to call snep::write multiple times?

diegosilvars commented 8 years ago

Hello. any news?

don commented 6 years ago

It looks like the extended frame's packet data is limited to 264, so changing the Seeed PN532 code won't help.

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Logical Link Control Protocol Technical Specification NFC - NFCForum-TS-LLCP_1.1 2011-06-20