NT3H1201 cannot be written via RF except connected to a micro-controller

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NT3H1201 cannot be written via RF except connected to a micro-controller

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xnormanw
Contributor II

Hello NXP-Forum,

 

I'm having troubles with my NT3H1201. It is connected to a micro controller, which enables the pass-through mode from Microcontroller to NFC, if a certain command is given via NFC/RF. After  using the passthrough-mode it resets the NC_REG from the session register to 0x01. This value allows commands being written via RF. But after unplugging the Microcontroller, this value is reset to 0x3C and I get the message "Write Tag Failed" using my program or NXP's Ntag tool. I'm not 100 % sure, why writing 0x3C on the Session Register denies me from writing on my NTag. 

Using the Ntag Info Tool didn't help either, since it tells me I'm able to write on the NTag. 

Thank you in advance and kind regards

 

Norman

 

P.S. I had a similair problem a half year ago, which I didnt find the solution back then. The work-around works, but not completely.

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6 Replies

869 Views
estephania_mart
NXP TechSupport
NXP TechSupport

Hello ,

 

The Pass-through mode bit (PTHRU_ON_OFF) can only be enabled when both interfaces (I2C and NFC) are ON. Could you please confirm you dis that ? 

Also, could you verify you did not change the configuration lock bytes?

lockNFC.png

 

Also you need to make sure that the direction PTHRU_DIR is set how you want to use it (RF to I2C).

Please help us checking this other post as it might also help you.

 

Regards,
Estephania

 

 

 

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858 Views
xnormanw
Contributor II

Hello estephania_mart,


thank you for your reply. I've checked and the reg_lock is set to 00. Besides that in the TagInfo app from NXP tells me that the configuration is changeable from I²C and RF aswell as that Memory access not locked and EEPROM write cycle possible. It still tells me "Write Tag Failed" with any apps I use. Reading is no problem at all and writing to it via I²C aswell.
The PTHRU_ON_OFF bit is set in the way I want to receive or transceive data. Since the Microcontroller is turned off, neither setting should change eeprom accessability, shouldn't it?  Anyways I have also put the PTHRU_ON_OFF bit to "RF_to_I²C" just for the case, but it still doesn't work.

 

Ah one thing which kind of would help me. I've the following session configuration:
[F8] 3D  00  F8  48
[F9] 08   01  01  00

If the NTag suddenly gets unavailable by RF the 3D changes to 3C. If disconnected it changes to 00. I understand the 3C, I dont understand why it doesn't change it back, but it doesn't occure that often so I'll care about in a different time. But how can I make the 3D stick? Or better question: Why does it only work, when 3D is written? I understand how this number value occures, but I dont understand why it's neccessary, since it primarily servers for the pass_through- function and direct communication between I2C and RF. Since the microcontroller ist turned off, this value shouldn't bother  the RF-communication?
Kind regards,

Norman Wiedemeyer

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838 Views
estephania_mart
NXP TechSupport
NXP TechSupport

Hello,

 

The Pass-through mode bit (PTHRU_ON_OFF) can only be enabled when both interfaces (I2C and NFC) are ON.

If there is not a field from an Active NFC Reader over the antenna of the NTAG I2C device, the bit will automatically reset to 0.

You can check this for more details.

 

Regards,
Estephania

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833 Views
xnormanw
Contributor II

Hello estephania_mart,

 

as I said the Pass-Through-Mode isn't an issue here, I want normal RF communication writing the eeprom, not the SRAM. Pass-Through works just fine, while writing the tag does not.

 

Kind regards

Norman

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828 Views
estephania_mart
NXP TechSupport
NXP TechSupport

Hello,

 

Could you please confirm you are accessing the memory as the memory map from the NFC perspective ? If you are accessing the memory you can't use the same addresses as you do in I2C as well as you can't send it with the same format as you do it in the I2C perspective. Please find the memory map in the datasheet of the NTAG I2C in chapter 8.3.1 Memory map from NFC perspective

 

Regards,

Estephania

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825 Views
xnormanw
Contributor II

Hello Estephania,

 

I'm writing the pages with the I2C NTag App. Also using the same write condition ("ultralight.write("data", dataformat). It works if the microcontroller is connected to the NFC Tag, but it does not, when it's disconnected.

 

Kind regards

 

Norman

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