ST25R3916B transparent mode configuration problems

[Jack_Chen]

前段时间使用ST25R3911B成功实现透明模式的通信，很遗憾的是ST25R3911B不支持负载调制，从而选择ST25R3916B作为替代。

目前已经将ST25R3911B透明模式的代码移植到ST25R3916B的芯片上，使用的是OOK的调制方式，移植之后发送数据的已调信号是正常的，接收的信号通过MISO引脚输出异常，如附件图片所示。MOSI引脚负责调制载波，理论上MISO输出的脉宽应该与基带信号一致，这点在ST25R3911B上可以验证。

问题1：ST25R3916B在透明模式的接收配置方面，相比ST25R3911B，是否需要更多的配置，避免出现附件里面的问题？

问题2：ST25R3916B是否支持在透明模式中，使用负载调制的方式发送数据？

Here is the machine translation:

Some time ago, ST25R3911B was used to successfully achieve transparent mode communication. Unfortunately, ST25R3911B does not support load modulation, so ST25R3916B is chosen as an alternative.

At present, the code of the transparent mode of ST25R3911B has been transplanted to the chip of ST25R3916B, using the modulation mode of OOK. After transplantation, the modulated signal of sending data is normal, while the received signal is abnormally output through the MISO pin, as shown in the attached picture. The MOSI pin is responsible for modulating the carrier, and theoretically the pulse width of the MISO output should be consistent with the baseband signal, which can be verified on the ST25R3911B.

Question 1: Does ST25R3916B need more configuration than ST25R3911B in terms of receiving configuration in transparent mode to avoid problems in the attachment?

Question 2: Does the ST25R3916B support sending data using load modulation in transparent mode?

Best regards

[Jack_Chen]

补充一点，在进入透明模式之前，同时使能发送和接收，意味着ST25R3916B在线圈上发送的数据，同时也可以被接收。这样可以简单测试芯片数据收发的情况，上面图片调制的脉宽是100us。

In addition, enabling both send and receive before entering transparent mode means that the data sent by the ST25R3916B on the coil can also be received. In this way, it is easy to test the data transmission and sending of the chip. The pulse width modulated in the above picture is 100us.

[Ulysses HERNIOSUS]

Hi,

I think you are looking at a difference in receivers: 3916 has a correlating receiver (unless dis_corr=1) and you will not see all the subcarrier pulse but a 1 while the chip detects the subcarrier.

Please also compare:

https://community.st.com/t5/st25-nfc-rfid-tags-and-readers/questions-about-configurations-of-st25r3916-for-transparent-mode/m-p/314074

https://community.st.com/t5/st25-nfc-rfid-tags-and-readers/st25r3916-transparent-mode-details/m-p/134598

BR, Ulysses

[Jack_Chen]

Hi,
感谢您的快速回复，如你所说，当我配置dis_corr=1时，透明模式的MISO输出波形确实有变化，但仍然不是预期的效果（如图片），我将研究相关器的配置。
另外，我只是需要将主机（ST25R3911B）发送的MOSI波形可以透明地传输到从机(ST25R3916B)的MISO，如果可以的话，请指出如何进行这样的配置。
后续将研究如何配置ST25R3916B做从机时以实现负载调制发送数据。

Thank you for your quick reply. As you said, when I configured dis_corr=1, the MISO output waveform of transparent mode did change, but it was still not the expected effect (as shown in the picture). I will study the configuration of correlator.

Also, I just need the MOSI waveform sent by the host (ST25R3911B) to be transparently transmitted to the MISO of the slave (ST25R3916B), if possible, please indicate how to do this configuration.

Later, we will study how to configure ST25R3916B as slave machine to realize load modulation to send data.

Best regards

[Jack_Chen]

Hi,
补充一点，当配置dis_corr=1时，如果把调制的脉宽改为10us（即MOSI），MISO的输出并不是预期的。
我想这个图片应该可以更好地看清楚波形的细节。

In addition, MISO output is not expected if the modulated pulse width is changed to 10us (i.e. MOSI) when dis_corr=1 is configured.
I think this picture should give you a better look at the details of the waveform.

[Ulysses HERNIOSUS]

Hi Jack_Chen,

I may have been mixing ST25R3916 and ST25R3916B. As ST25R3916B has only the correlating receiver not sure if dis_corr=1 still works. What was your setting of om and targ bits? 

With targ=0,om!=0 you should get reader mode operation.

With om=0,targ=0 you would be selecting an AP2P mode.  And to your previous question: targ=1,om=1 would be passive target mode. In both modes MISO will have NFC-A demod, and IRQ NFC-F demod.

Especially for reader mode you should also set the all the analog receiver settings (low pass, high pass, etc.)

BR, Ulysses

[Jack_Chen · Accepted solution]

Hi,
我想使用的是透明模式，对于targ和om位，使用的是默认值，即targ=0,om=0001B。
我使用的开发板是X-NUCLEO-NFC08A1（ST25R3916B），作为从机使用，同时使能tx和rx；主机使用的是ST25R3911B。
现在，在透明模式下，主机已经实现通过MOSI将基带信号透明地传输到从机的MISO。至于先前提到的情况，可能是模拟接收器的设置问题，我需要更多的时间调试，如果您有好的建议，也希望可以告诉我。
后面我可能会有一些关于在透明模式下的负载调制问题。

I want to use transparent mode, and for targ and om bits, use the default values, i.e. targ=0,om=0001B.

The development board I used was X-NUCLEO-NFC08A1 (ST25R3916B), which was used as a slave with both tx and rx enabled. The host uses ST25R3911B.

Now, in transparent mode, the host has achieved transparent transmission of baseband signals via MOSI to the MISO of the slave machine. As for the situation mentioned earlier, it may be the setting of the analog receiver. I need more time to debug it. If you have any good suggestions, I hope you can tell me.

I may have some questions later on about load modulation in transparent mode.

Best regards