[M24LR16E] - Question about the WIP/RF BUSY output pin

[danilo]

Posted on January 23, 2014 at 16:48

Hello to all,

I have a question about the WIP/ RF BUSY pin operations.In my application I set such pin to indicate a write in progress (namely the WIP function).The datasheet states that this pin remains low until the RF write process is completed. Next, it comes back to high-z status.Now I'm a bit confused regarding the definition of a ''complete write process''. In fact, I expect that the pin is tied low at the beginning of the write, it remains low during the writing of a number n of bytes and finally it return back to high-z status at the end of the process.The attached file is the screenshot of the WIP/RF BUSY signal obtained during the writing of a small NDEF message (a total of 30 bytes).The screnshot shows that the pin is tied low and return high several times before completing the write process.Can someone accurately explain how does the WIP/ RF BUSY pin work? RegardsD.Porcarelli #rf-wip-busy #m24lr16e #m24lr16e #m24lr16e #rf-wip-busy

[Anais GALLIGANI]

Posted on January 24, 2014 at 09:53  

Hello ,

In order to understand what happens ,might you please tell me what is the command that is send ?

Thanks,

Have a nice day,

Best regards,

ST NFC/RFID Dynamic tag support

[danilo]

Posted on January 24, 2014 at 14:06

Hello,

thanks for your reply. I used a generic smartphone app to write a NDEF text message. The message was ''qwertyuiopasdfghjklzxcv''. The app states that the total number of byte to be written is Meanwhile, i tried to write the same message by using the NFC-V reader app from ST. The resutling waveform of the WIP/RF BUSY signal is plotted in the attached file Regards D.Porcarelli ________________ Attachments : st_app_waveform.png : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HzIR&d=%2Fa%2F0X0000000bKZ%2FsZHWuv79hGHjPs4uo_HYlKBjxkVe8ji_LJ_WVJTPEKg&asPdf=false

[Anais GALLIGANI · Accepted solution]

Posted on January 27, 2014 at 10:17

Hello,

Onthe M24LR, there is only Write Single Bloc (4 bytes)

Soif you write 30 bytes, there is 8 separated write so your curve seems ok.

Andthe 9th might be the write of the length.

Whenit is needed to write inside, the procedure is as follow :put length at 0, change NDEF, update length.

Best Regards,Have a nice day,ST NFC/RFID Dynamic tag support