ST25R3911B : RFAL Library : st25r3911OscOn() giving Error=1 on Custom Board

[vaibh_p]

Hi ,

We have done preliminary test on X-Nucleo-NFC05A1 and than made our custom board using the reference circuit provided.

We have followed the sequence for Card Detection:

Now the the function work as follows:

• rfalInitialize() gives ERROR_NONE
• st25r3911OscOn() which is giving the error =1(ERR_NOMEM).
• rfalFieldOff() gives ERROR_NONE
• rfalNfcvPollerInitialize() gives ERROR_NONE
• rfalFieldOnAndStartGT() gives ERROR_NONE
• rfalNfcvPollerCheckPresence() gives the error=4 (ERR_TIMEOUT)

So before and after this function st25r3911OscOn() , everything looks good , just we are not getting what causing the error in st25r3911OscOn().

We have connected the 27.12MHz Crystal.

Also we have noticed that frquency of 9MHz on CRO across the crystal, so it is Okay ?

Moreover need a review on Power Supply section of the schematic.

I am attaching the screenshot , and in this

we have kept R7 Open and +5V Not Connected.

So any guess what is causing the issue ?

[vaibh_p]

Hi Brian and Travis ,

I have made changes as suggested by you guys. Thanks for that.

Following are the observations:

1. st25r3911OscOn() is returning ERR_NONE.
2. rfalNfcvPollerCheckPresence() is now returning ERR_TIMEOUT i.e. Error No. 4
3. We have connected "R6 and R16" and kept "R7" open , i.e. providing VDD and VDD_IO with 3.3V supply.
4. One thing we have noticed that , we had misplaced the Capacitor in Antenna Circuit "680pF_50V" , so we have connected their parallel combination of "470pF+220pF" , so will it cause problem in detecting Tag ?
5. The frequency across the crystal is still the same i.e. 9MHz , I have attached the picture of that.

So I guess we are very close now in detection of tag , so please guys suggest something which are creating the problem.

Thanks a lot for your help till now!!!

[Travis Palmer · Accepted solution]

Hello Vaibh_p,

If components are missing in the matching circuit, you will most likely have problems detecting the tags. This can cause either a reduced detection range or no detection at all.

It seems, that there is something wrong with your crystal. It should either resonate at 13.56MHz or 27.12MHz. The bit "osc" in the IO Configuration Register 1 has to be set accordingly. Can you maybe populate the crystal of the ST25R3911B-DISCO or NFC05A1?

I just measured the XTI pin of the ST25R3911B-DISCO.

BR Travis

[vaibh_p]

Hello Travis ,

You are absolutely correct , the problem is due to crystal.

Actually the entire Crystal lot we have ordered are damaged one , since we have checked with multiple crystals for appropriate frequency.

Meanwhile we have managed to get another 27MHz crystal from old pcb and bingo , that worked and resonate at 27MHz and now the board is capable of detecting the tags.

While we are working on detection range now , as for now for our antenna size is 5cm*4cm and the tag size is 3cm Circular , with this setup we are getting range of approx 3 to 3.5cm.

So any links or threads related to increase the range ?

One question , can we achieve the good range near about 10cm as it is ISO15693 Technology by keeping the reader antenna size small and tag antenna size large ?

For your help till now, Thank you so much @Travis Palmer_O​  and @Brian TIDAL_O​  , we are really grateful for your help guys.

[Travis Palmer]

​Hello,

Using the NFC05A1 (47 mm x 34 mm, four turns, 13.56 MHz inductive antenna etched on PCB and associated tuning circuit) the average read range  of ISO14443A tags is around 60 to 70mm and 110 to 120mm of ISO15693 tags.

It always depends on tag antenna size, tag resonance frequency and power consumption of the tag.

Since the NFC05A1 is designed to serve all technologies and bitrates (even VHBR) there is still some room for improvement.

But it is a good starting point. How big the card antenna will be at the end mostly depends on the application.

BR Travis

[vaibh_p]

Okay , Thank you Travis. We will look on the above points while designing tags.