Reading NFC tags, cannot get UID

RE: Reading NFC tags, cannot get UID

Rokas — Tue, 29 Nov 2016 13:45:33 GMT

I'm still waiting for my logic analyzer to be shipped to me, it's the third week and I still haven't got it. So i thought I could skip it up and think of probably more cases that might be the issue. Yes, I double check all the pins at least every day. This is quite a solution, I didn't thought about connecting both of the board via SPI, thanks, maybe that will lead me somewhere.

RE: Reading NFC tags, cannot get UID

Hung Bui — Tue, 29 Nov 2016 11:40:54 GMT

@Rokas: Maybe you can try to use a logic analyzer to track down what is sent over SPI pins.

Make sure your TI chip won't hold the CLK pin low when the nRF51 clocking out. I assume you connect all four pins CS, SCK, MOSI, MISO correctly.

Have you tried to test SPI with 2 nRF51 boards ?

RE: Reading NFC tags, cannot get UID

Rokas — Tue, 29 Nov 2016 11:29:28 GMT

Ok, so what I found out is that trying to communicate with SPI it gets to a while cycle, that doesn't jump out. In the source file nrf_drv_spi.c it goes to while (!nrf_spi_event_check(p_spi, NRF_SPI_EVENT_READY)) {} nrf_spi_event_clear(p_spi, NRF_SPI_EVENT_READY); and never jumps out. Is this a problem with the TI equipment, or is there something else with the communication?

RE: Reading NFC tags, cannot get UID

Hung Bui — Mon, 28 Nov 2016 11:59:28 GMT

I would suggest to post your question on TI forum.

Before trying to get the ID of a Tag, you should better try to write/read registers and FIFO inside the TRF7970 just to make sure you can communicate to the TI chip correctly.