The ANT7-ST25DV04K module disables the NFC of the mobile phone.

[Ide c.1]

I am having problems with the ANT7-ST25DV04K module. What happens is that when I bring the mobile close to the module to read it, the NFC of the mobile is activated and deactivated all the time and never finishes reading the card. 

I'm using the ST25 NFC Tag app, but I can't do anything because it doesn't detect the module for the reason I mentioned before.

Any solution?

[JL. Lebon]

Hello,

What do you mean exactly by "NFC of the mobile is activated and deactivated"?

Have you tried with a different reader of smartphone ?

The ANT7-ST25SV04K antenna is very small. It needs to be well aligned to the phones antenna and close enough so that power transfer is good. Sometimes, the antenna on the back of the smartphone is difficult to find as most of the time its position and size is not indicated. You may encounter this strange behavior may be because you have not correctly aligned the antenna's phone and the ANT7 ?

Best regards.

[Ide c.1]

Hello,

What I mean is that when I bring the ST25DV04K close to the mobile, the NFC symbol of the mobile starts to blink, that is to say, it turns off and on by itself. It is not a problem of aligning well, I have well located in which part of the mobile is transferred more power. 

I have 3 ANT7-ST25DV04K modules and 1 works correctly. The other 2, give me the failure that I mentioned above and I can not use them. I hope it can be fixed somehow.

Best regards.

[Ulysses HERNIOSUS]

Hi,

of course also mobile phones can have bugs. Which brand and model of mobile do you use? Does it also happen for other models?

If you have 1 out of 3 working properly I would suspect that they contain different data and mobile encounters a bug on some content. How are the tags formatted? I would go and compare their memory content, especially the CC file.

Best Regards, Ulysses

[Ide c.1]

Hi,

I am using Samsung Galaxy S6 and Huawei P8 Lite. The same failure occurs on both phones. 

How can I compare their memory content? I mean, with the help of the phone I can not. If I use I2C with the help of the microcontroller, with which command can I read the CC file?

Best regards.

[JL. Lebon]

Hi,

You can read the CCFile from I2C by reading the first 4 bytes of the user memory, at address 0x0000.

This is done with the following I2C command:

S/0xA6/sA/0x00/sA/0x00/sA/S/0xA7/sA/CC0/mA/CC1/mA/CC2/mA/CC3/mNA/P

Where: S=Start, sA=Slave Acknowledge, mA=Master Acknowledge, nNA=Master Not Acknowledge and P=Stop (it is possible to split the command in two by inserting a Stop before the second Start).

You can read more than 4 bytes in a single I2C command if you want to see what is after the CCFile.

Do you have any NFC/RFID reader (like ST25R3911 or CR95HF) you can use in place of smartphones to try to read the tags ?

Best regards.

[Ide c.1]

Hi,

Through I2C everything works correctly. I have been able to read the memory without problems, the problem is when I try to do it through NFC. I don't have any readers other than a mobile phone, maybe that is a solution.

Best regards.

[Ulysses HERNIOSUS · Accepted solution]

Hi,

the content should be the same from I2C and NFC. Please compare the contents received from I2C. The hypothesis is that some invalid content in the CC (Capability Container) triggers this behavior on smart phone.

BR, Ulysses