WUPA response

[smiwa]

Hi Christian san,

I have a question again about PN5180 and BasicDiscLoop libirary. My prototype looks start working but I have no ATQA form PN5180.

 By observing oscilloscope, RF emission is no problem by RF ON command, and it looks BasicDiscloop is executed correctly. But no RX IRQ for ATQA is received.

In this case, what, do you think, is the most possible cause? Very sorry for this ambiguous question but please give me your any idea?

Thank you for your supports every time!

Best regards,

   S. Miwa

[smiwa]

Hi Christian san,

Please find the attached for the oscilloscope&Logic analyzer waveform. This figure is at the timing of WUPA command send (0x09+0x07+0x52 as SPI data). (triggered by "09" bit pattern)

RF field is already on before this command. After this command, ASK for "0x52" is expected but actually I got the some intermittent emission.

So, could you help me to check the possible causes for further  investigation as I think if I solve this issue I can get communicate to cards.

Thank you for your help!!

Best regards,

   S. Miwa

[smiwa]

Hi Christian san,

Thank you for your advise and I confirmed no REQA/WUPA command is emitted from antenna by using oscillocsope and NFC protocol analyzer MICROPROSS MP300 ACL1.

So, I think some initialization to PN5180 or transceive statemachine commands do not work. What do you think I should check ?

Thank you for your supports!

Best regards,

   S. Miwa

[smiwa]

Hi Christian san,

Thank you for good advise! I can see only RF field and cannot significant change of its amplitude. So it means REQA command does not work?

Could you advise me what approach should I take to investigate this cause?

SPI function applicable to my system was made by ourself. (its read/write to register function is confirmed because RF field can get on and off) 

Best regards,

   S. Miwa

[christianeisend]

Your assumption is correct, since you are able to see an RF field, SPI communication seems to be working.

Still, would like to see the SPI communication. Is it possible for you to trace the SPI communication using a logic analyzer? SPI lines + BUSY and IRQ during a REQA-ATQA cycle. Just upload the file here and let me know which tool you are using.

Christian. 

[christianeisend]

Do you see only the RF field on the oscilloscope or also modulation of REQA?

REQA modulation is usually quite easy to detect since Type A communication performs 100% ASK modulation - you should see 7 short (2-3us) RF off pulses. In case PN5180 doesn't send REQA, it will not be receiving ATQA of course.

ATQA is also visible on oscilloscope, but you need to reduce the contrast of the scope to see it. an ATQA usually follows 86us after the REQA.

Can you please check and confirm if you see both, REQA and ATQA using oscilloscope?