AnsweredAssumed Answered

CR95HF No Response

Question asked by paralikar.pranav on Sep 10, 2014
Latest reply on Sep 14, 2017 by NFC software support 3

Hi,

I have designed a CR95HF based Board. The circuit diagram is exactly as per the 0018253A PLUG-CR95HF-B.pdf found on the ST Website. I have tried to match the PCB layout of my board to this board as far as possible. I have selected the communication interface to be UART. Initially, I want to communicate to the CR95HF using a terminal s/w (Docklight) running on PC using a USB to UART Converter. I have set the parameters to 57600-N-8-1 and No Flow Control. I want to use ISO/IEC 14443 Type A as communication protocol and the NFC Tag I am using is of NFC Forum Tag Type 1 (Topaz).

When I send command 0x0100 (IDN) to the CR95HF, I get 0x000F4E4643204653324A415354320075D2 in response. When I send 0x55, I get 0x55 in response. When I send protocol select command 0x02020200 or 0x020402000300, I get a response of 0x0000. But when I send any command after this command like 0x09043A005804 or 0x0904680101D1 or 0x04022607 (given on the page no. 52/53 of CR95HF Datasheet), I get no response from the CR95HF. I need to hard RESET the Board. While doing all this, the NFC tag is kept on the antenna of the PCB.

Another observation is while seeing the RF waveforms at the antenna side of the CR95HF. Until I send the protocol select command, I don’t see any RF waveform on the antenna side, as soon as I send the protocol select command, I am able to see these waveforms, but then the CR95HF does not respond to any commands.

Why is this happening?? Am I missing anything here?

Could anyone please let me know the exact procedure to read/write to an NFC Tag using CR95HF and Docklight and USB to UART Converter?

Please note: The NFC Tags I am using can be read/written using an NFC enabled Smart Phone with the help of NFC Easy Connect App available on Google Play.

Please help me in this as I am new to this.

Awaiting for your reply.

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Thanks & Regards,
Pranav

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