CR95HF No Response

[pranavparalikar]

Posted on September 10, 2014 at 13:02

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.

--

Thanks & Regards, Pranav

[Wei Lu]

Posted on September 13, 2017 at 11:28

Hi,

I have a question about controlling NFC with microcontroller through UART.

SSI_0 and SSI_1 are connected to ground and I send 0x00 by host mcu earlier before I send the first command.

However, I don't get any response from CR95HF. May I ask you what's your steps to implement it?

Thanks a lot.

Wei Lu

[Rene Lenerve · Accepted solution]

Posted on September 14, 2017 at 16:04

Hi

to_deletemichele fazzini

,

   If the ST95HF responds to the IDN and ECHO commands,

this informs of the good communication through UART. The problem seems to be with the tag. Can you test your commands without the tag in the field and see if the CR95HF is answering ?

   Command 0x09043A005804 and 0x0904680101D1 are 'write register' to the CR95HF and should answer 0000 (Not an RF command so no interaction with the tag, CR95HF should always answer).

   Command 0x04022607 is a SendRecv command sent to the tag, without a tag in the field CR95HF should return 8700 ( Frame wait time out or no TAG ).

   Until a protocol is selected, this is a normal behavior that there is no activity on the RF side. The CR95HF need at first a protocol to send RF commands. Only SendRecv should send RF command. Other commands are used to configure the CR95HF.

You say that you are able to see waveforms from RF antenna, can you capture some frames when you are sending a SendRecv command from the CR95HF?

Best Regards.

[Rene Lenerve]

Posted on September 14, 2017 at 16:10

Hi

Lu.Wei.003

,

Can you create a new discussion for your question.

This will avoid misunderstandings in the answers with those of the thread's owner and will make your question visible to more forum people for better answers.

I recommend that you read the

http://www.st.com/content/ccc/resource/technical/document/datasheet/d2/cc/cb/f6/7c/63/48/75/DM000256pdf/files/DM000256pdf/jcr:content/translations/en.DM000256pdf

in section 3.2 Startup Sequence to properly initialize the CR95HF before trying to communicate with it.

Hope this can help

Best Regards.