Hi:
I am developing the spi protocol driver in Linux for TRF7960. After some customization on the spi master device driver, I can read and write TRF7960' s registers.
My goal is to read the uid of a credit card, so I referred to this document: SLOA136 - Implementation of ISO14443A Anti Collision Sequence in the TI TRF796x
What I have done is:
1. set registers:
reg00(Chip status control) = 21
reg01(ISO control) = 88
2. Send REQA Command:
I sent 2 data arrays: 8f 91 97 3d 00 10, 3f 26 00. I also tried one array 8f 91 3d 00 10 26, but it doesn't always work.
What I got:
I could always see the end of TX (bit 7) on register 0C(IRQ status) which made me happy. However, The other bits confuse me:
START of RX (bit 6): sometimes it is set when there is no card around, but most of time when I placed a credit card on the chip, it was not set.
SIGNALS of FIFO (bit 5): sometimes is was set, so I went check the FIFO status register (1C). It kept changing. When I read the fifo, the count of the FIFO doesn't decrease by 1.
Here are my questions:
1. What is the correct settings to communicate with ISO 14443A promixity cards?
2. Is there a working Linux protocol device driver to TRF7960, so I can use it to read a credit card or compatible promixity cards?
Thanks
Kevin
