• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 16 subscribers
  • Views 898 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TRF7960A: IRQ Reg read gives only 0x80, 0x3E and next interrupt is 0x00 and 0x3E

Shravan p
Prodigy 10 points
Part Number: TRF7960A
Other Parts Discussed in Thread: TRF7960

Hi,

I have used STM32 with TRF7960A in my custom board with ISO15693 tags provided by TI along with TRF7960A_EVM kit. I can read a TRF7960 register and I can even write successfully. I have used sloa251 driver files in my project and I observe that after sending the inventory request as described in the TRF datasheet

1) IRQ is received and its status reg value is  0x80,0x3E and next successive IRQ is received and its status is 0x00,0x3E, but as per the datasheet I need to 0x60. May I know what is the reason for this? I have read all the registers and cross checked with the EVM register read and both are same. 

2) I have my stm32 SPI configured for CPOL is low and CPHA is high (2nd edge) MODE 1. Do I have to make any changes in the SPI mode while reading FIFO? (As per datasheet modes should be changes for hardware SPI) 

3) Under what conditions FIFO can be empty? (Even tx_out , RX1 and RX2 output are tested and are as desired.)

  • 0
    TI__Guru*** 135355 points
    Hello Shravan,

    The driver from the old TRF7960AEVM project isn't the greatest, I would recommend using our latest driver for the TRF7960A. You can download the code here: www.ti.com/lit/zip/sloc297

    Then just change the #define TRF79xxA_VERSION in the trf79xxa.h file to be 60 instead of 70. The driver will then be automatically configured for the 60A.

    Answer for #1 - tag did not receive command properly and did not reply. Please use updated driver/firmware as mentioned above.

    Answer for #2 - You need to change SPI clock polarity between read/write operations. While you can't use the TI SPI driver, I recommend viewing it to see how we handle it with our MCU.

    Answer for #3 - FIFO will be empty after it is Reset OR all it's contents are read out. It will not fill unless a tag reply has been processed.