HTRC110 tag not responding to command via WRITE_TAG

[egonc]

We are trying to read the UID from a HTMS8001 using a HTRC110 and a microcontroller. Giving for granted that the TTF mode is working properly and we are able to decode its content, we are not succeeding in getting the UID from the TAG via READ UID command.

We already checked the HTRC110 datasheet, AN98080 and HTMS8x01 datasheet to check how to do the procedure which is implemented as follows:

- setup the reader by setting config pages, sampling time and general settling

- (leave the tag to enter TTF while doing other stuff)

- assert TX disable and wait 6ms to reset the tag and leave TTF mode

- remove TX disable and wait 3ms to enter mode switch time window

- start fast settling and enter TX_MODE_N. Use DIN to generate pulses on coil (SOF, flags = 0, cmd = 2, EOF ... no CRC)

- complete fast settling and enter READ_MODE

- wait for data

At this point the tag is never loading the carrier until the 5ms timeout from EOF expires and it enters TTF mode. 

We already tried several combinations of timings without success, including sending the cmd several times, using the switch mode sequence and testing several tags.
Is there any step missing or a bad procedure?

We had a look at rc110lb6.zip, but has no more information that the docs and everything seems ok with the exception of nomenclature about START_AUTH vs READ UID command.

Pictures attached:

1: overall view of signals

2: previous TTF, field off, 6ms delay, field on

3: wait for mode switch window, settling (first step) and WRITE_TAG (n is configured in setup)

4: command data, end of settling and START_READ (no load shown on the coil trace)

5: still no load untile 5ms from EOF, then back to TTF because of timeout

Traces as follows:

red: tag coil

green: DOUT

yellow: SCLK

purple: DIN

Kind regards

[egonc · Accepted solution]

Yes we tried and the behavior was exactly the save, although, after improving the coil tuning the tag started to replying to our commands.

I'm not sure what really happened there as the modulation seemed "good enough" looking at the numbers on the datasheet, but obviously there were some issue on the electrical side.

Thank you for helping

[egonc]

Hi Kan,

thank you for looking at this issue.

The scope capture was not a SWITCH but a READ UID command which is starting with a SOF. Your A and B marks are the commands to HTRC110 for turning on the carrier (A) and WRITE TAG (B).

After B HTRC enters transparent mode and the  SOF, FLAGS (5bit value 00000), READ UID CMD (6bit value 000010) and EOF is sent.

I will take another picture as a reference of the bit stream sent to the TAG.

After the EOF I expect the tag to start loading the carrier but nothing happens until the 5ms timeout expires and the tag enters TTF mode again.

Thank you,

Egon

[Kan_Li]

Hi @egonc ,

Thanks for the clarification! I understand now, but have you ever tired with the switch mode command issued at the same point? Did it work ? or the problem is still there? Please kindly clarify.

Thanks for your patience!

Have a great day,
Kan

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[Kan_Li]

Hi @egonc ,

Thanks for reaching to us! 

I am wondering if the switch mode command has been correctly issued at the right time, would you please tell me at which point this command was sent to the tag referring to the following snapshot?

and for the switch mode command, it should be 5 bits of "00011", while from the snapshot, there were more than 5 bits which started with  01000...

Would you please clarify? 

Have a great day,
Kan

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- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
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