SDK13 nfc_t2t_payload_raw_set() not work properly.

[Valer_I]

Hello, I use SDK example nfc_text_record for pca10040 DK. With aim to check memory area of the emulated tag I've modified example with next:

 /* Set up NFC */
    err_code = nfc_t2t_setup(nfc_callback, NULL);
    APP_ERROR_CHECK(err_code);

	static const uint8_t key[16]={0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,0x10};
	err_code = nfc_t2t_payload_raw_set( key, 16);
    APP_ERROR_CHECK(err_code);

    /* Start sensing NFC field */
    err_code = nfc_t2t_emulation_start();
    APP_ERROR_CHECK(err_code);

    while (1)
    {
        __WFE();
    }

After reading with cardreader:

Pages:

04     00 00 00 00     90 00
05     05 06 07 08     90 00
06     09 0a 0b 0c     90 00
07     0d 0e 0f 10     90 00

so the question is why nfc_t2t_payload_raw_set() skip writing page 4 while perform writing of pages 5-7?

[Michal]

Hi, the problem with your code is, that you use const for the NFC raw payload storage. The nRF52 Product Specification states that the NFCT peripheral uses EasyDMA, which requires an address in RAM space. And maybe the SDK documentation is missing that... So it will not work if your data is stored in Flash. To be precise it will do the following: if your flash address is 0x00000234, NFCT will use data from 0x20000234 so it may read random data from some location in RAM!

Hope this helps.

Regards, Michal

[Valer_I]

Thanks! After removing static const modifier I works fine.