How can I set ST25R3911B-AQFT for ISO14443A demodulation?

[SIHUNKIM]

Hi All,

I am trying to demodulate the signal of ISO14443A&B using ST25R3911B. In the case of Type B, I was able to receive data well by setting the type setting and Bitrate, specifying the preset with a direct command, and then setting the unmask. However, in the case of Type A, I checked while changing several registries, but the FIFO data was empty. By capturing the waveform directly with the analog pin, I was able to confirm that the data was coming out well.

So I think it's a registry setting issue, so please let me know if there is anything I need to check regarding this.

[Ulysses HERNIOSUS]

Hi Sihunkim,

 

the approach you describe should work, however along the way of ST25R3911B it was discovered that the settings done by analog preset are not always optimal (e.g. for FeliCa) and our drivers are not using this command anymore. RFAL is manually setting registers similar to the ones done by AnalogPreset.

You say you are seeing outgoing modulation. On which analog pin? Which command do you send? How are you sending it? Do you observe also a response in the field?

Maybe you can share some scope shots, etc.

 

BR, Ulysses

 

 

[SIHUNKIM]

Hi Ulsses,

I want to put REQA as an analog source in another device and see the digital data coming out as FIFO from the ST device.

However, this did not work, so I set it to test mode for debug and checked the analog signal at the CSI pin.

That signal is:

Looking more closely, in the case of Type A, I confirmed that the signal below matches the target value of 04 00 after Demodulated + Gaussian filter, before data parsing. So, I was thinking that the reason there was no response from the FIFO in Type A was the register setting, but I don't know how to set it, so I'm asking.

 

[Ulysses HERNIOSUS]

Hi,

the answer to REQA (and WUPA) are quite special frames as no CRC and no parity is included. With default settings I assume that it will be decoded with error and depending on settings of crc_2_fifo nothing may end up there.

Please look also at IRQ status registers and the interrupt for reception, framing and error.

Normally when using the direct commands for REQA/WUPA the reception should automatically be started with correct setting. Maybe your manual unmask receiver is garbling the settings.

Please have  a look at no_crc_rx. Possibly you could also play with no_rx_par and crc_2_fifo.

 

BR, Ulysses