Register settings for st25r3911b for ISO 15693

nicolai geske · ‎2018-06-14

Posted on June 14, 2018 at 12:50

Hello ST25 community.

Some weeks ago I wrote this thread:

https://community.st.com/0D50X00009XkWIeSAN

I got the coding as in the example and it works. (The bytes are coded as it is mentioned in ISO 15693 datasheet)

I want to use 1 out of 4 coding for transmit from VCD to VICC:

Following register settings are used:

Defined: MSB to LSB ( 7 to 0 )

*-----------------------------------------------------------------------------------------------------------*

*register settings for iso15693*

Mode Definition Register (0x03) : 0 1 1 1 0 0 0 0 - sub carrier stream mode

Bit Rate Definition Register (0x04) : 0 0 1 0 0 0 1 0 - bit rate fc/32

Stream Mode Definition Register (0x08) : 0 0 1 1 0 0 0 0 - sub carrier frequency fc/32 , sub carrier pulses 4, time period fc/128

Auxiliary Definition Register (0x09) : 0 0 1 0 0 1 0 0 - set modulation AM

AM Modulation Depth Control Register (0x24) : 0 1 1 0 1 1 0 0 - set modulation depth to 29.7

After these settings I use following direct commands:

send_direct_command(RFID_CALIBRATE_MODULATION_DEPTH);

send_direct_command(RFID_CALIBRATE_ANTENNA);

For the st25r3911b power up I use following settings:

IO Configuration Register 2 (0x01) : 1 0 0 0 0 0 0 0 - set power supply of ST25 to 3.3 volt

Operation Control Register (0x02) : 1 1 0 0 1 0 0 0 - enable (set to 1): en, rx_en,tx_en

send_direct_command(RFID_ADJUST_REGULATORS);

*-----------------------------------------------------------------------------------------------------------*

I'm not sure if these settings are right. Hopefully someone could check.

As an attachment I send the communication VCD to VICC on an

oscilloscope. I got this using a different antenna.

Best regards

Nicolai.

nicolai geske · ‎2018-07-11

Posted on July 11, 2018 at 10:40

Hi Ulysses,

I think I have found the problem why I get no response from the VICC. But first thinks first.

I have updated my code.

#define ISO15693_SOF_1_4 0x21

#define ISO15693_EOF_1_4 0x04

#define ISO15693_00_1_4 0x02

#define ISO15693_01_1_4 0x08

#define ISO15693_10_1_4 0x20

#define ISO15693_11_1_4 0x80

My dataword looks like that:

PART VALUE CODED

SOF 0x21 0x21 uncoded

FLAGS 0x26 0x20 0x08 0x20 0x02

CMD 0x01 0x08 0x02 0x02 0x02

MASK VALUE 0x00 0x02 0x02 0x02 0x02

CRC_LOW 0x09 0x08 0x20 0x02 0x02

CRC_HIGH 0xF5 0x08 0x08 0x80 0x80

EOF 0x0404 uncoded

So in total I have: 21 20 08 20 02 08 02 02 02 02 02 02 02 08 20 02 02 08 08 80 80 04

This is what I write to FIFO and send out using 'transmit without crc'.

Still I get ABSOLUTLY no respone. I checked your CRC function with mine and I got the same values.

So I gave another shot to the

oscilloscope (I used an antenne of Proxmark to get the value).

In order to see what happends I made an endless loop: just fill the FIFO and transmit the values via magnetic field.

In the case nothing is transmitting ( the picture) I have only my carrier (56 MHz).

In the case the FIFO is only filled with 0xFF (31 bytes in total) a modulation takes places.

BUT in the case the FIFO is filled with constant 0x00 (31bytes in total) there is a modulation too.

Here is my endless loop:

while(1){

//needed befor sending Transmit CRC / no CRC

send_direct_command(RFID_CLEAR);

// this function takes a number of bytes to be written (fullbytes) and a number of bits and an array of uint8_t values

set_full_bytes_and_single_bits_for_transmitting_and_write_data_to_fifo(31, 0, fifo_write_data_iso15693)

send_direct_command(RFID_TRANSMIT_WITHOUT_CRC);

}

Best regards, Nicolai.

________________

Attachments :

no_transmit.jpg : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HxR1&d=%2Fa%2F0X0000000ay0%2F4NYg6kULkvkpe_A1oQJrmgYm1flTkbGA5.ehdPGz844&asPdf=false

transmit_constant_00.mp4 : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HxQw&d=%2Fa%2F0X0000000axz%2FWQOzCyXf1nzaDCArCLyBPsnx2d.SNAmxF5UhgKfpj8E&asPdf=false

transmit_constant_FF.mp4 : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HxQr&d=%2Fa%2F0X0000000axy%2FWotFZkVZohTi0xxTPaqpfA0S3peVHGnzegFDfc6FHsw&asPdf=false

nicolai geske · ‎2018-07-12

Posted on July 12, 2018 at 10:42

Hello

Ulysses,

there should be one picture and two videos as attachment. Both videos about three seconds showing the measured wave by the

oscilloscope

.

I started developing and implementing the code using the official iso 15693 datasheet. For example the 1out of 4 coding:

As you can see, the values for coding are LSBIT first but also inverted.

This total confused me. So i came to this forum. To sum it up: I implemented the same functions but with inverted values and LSBIT first. This was your ''confusion'' about my code .

I'm going to implement the invertion of crc and will give feedback.

Best regards, Nicolai

Ulysses HERNIOSUS · ‎2018-07-12

Posted on July 12, 2018 at 08:44

Hi Nicolai,

if you read our source code you will find that for iso15693 the crc needs to be inverted at the end - before coding:

26 01 00 F6 0A -> 21 20 08 20 02 08 02 02 02 02 02 02 02 02 20 08 80 80 20 20 02 02 04

You are going through a lot of hassle for re-implementing what we have already implemented.

Not sure why you would observe modulation on sending 0x00. No picture was attached.

Regards, Ulysses

nicolai geske · ‎2018-07-13

Posted on July 13, 2018 at 15:44

The original post was too long to process during our migration. Please click on the provided URL to read the original post. https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I6th&d=%2Fa%2F0X0000000bxb%2F9AfLJqNvPSmbIXozj8z0tVPu9iFyI6_wtnTsWFgj4MM&asPdf=false

nicolai geske · ‎2018-07-25

Hello,

i got it work 🙂

The trick (mistake) was to set the transmission to OOK not to AM.

Thank you again for your patience.

Best regards, Nico