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TRF7960 for embedded project

Benjamin Deforge
Intellectual 270 points
Other Parts Discussed in Thread: TRF7960A, TRF7960

Hi, 

I am currently working on a embedded project, I use the TRF7960A EVM, running the firmware for ST EEPROM chips (with extended protocole : see http://e2e.ti.com/support/low_power_rf/f/667/p/114720/409794.aspx#409794) ). 

The EEPROM chip is embedded on a PCB and connected in I2C with a PIC microcontroller. The problem I am having is the following : when I plug the EVM in the USB port of my PC, the eeprom is powered on and the I can tell that the program is running. But as soon as I start the GUI and open the serial port, the program is blocked ...

 

Basically, the program leaves a time slot for RFID dialog. the RFID writes a command code corresponding to an action to perform, and stores the result in the eeprom. The RFID then goes and read the eeprom area where the result is stored. 

i've checked the firmware documentation and seen that as soon as the COM port is open, the TRF enters Hostcommands() ...

Maybe you'll have an idea to debug this issue ! 

 

thanks in advance ,

 

  • 0
    TI__Guru* 91206 points

    Benjamin -

    am i understanding you correctly here you are expecting the EVM to remain in the polling mode after Host has been enabled? Please provide some more detail here as to the setup and exactly what you expect here. ISO15693 Host Commands document for the EVM is here ==> http://www.ti.com/litv/pdf/sloa141

    Josh

  • 0 in reply to Josh Wyatt
    Intellectual 270 points

    Thank you for your answer, i am sorry if my request was not clear enough.

    My system is the following :

    The TRF7960EVM is connected to the USb port of my PC, where I have an home made GUi running (specific for my application), and wich sends the ISO15693 commands as described in the manuals.

    I am sending requests to a ISO15693 dual access EEPROM (ST M24LR64), implanted on a PCB with an antenna. This PCB is like my tag. A MCU is also embedded on that PCB, and it sends I2C requests to the EEPROM. The whole problem is the dual access that needs to be as synchronised as possible, that's why I ensure that I2C requests are sent (from the MCU to the EEPROM), and I leave time slots with I2C disabled for RFID dialog.

    The program implanted in the MCU is running right when the TRF7960 is connected to the PC but COm port is not opened yet. As soon as I open the COM port, my program is blocked, and I assume it is because the I2C is no longer available... After checking all documentation and firmware sources, I have learnt that until data is received from the PC, the TRF7960 performs an ISO15693 polling sequence, and as soon as data is received, it listens for commands. Is that right ?

    What is fundamentally different, regarding the chip state, when the COm port is open or not Open ?

     

    I hope I am making myself understandable ...

     

    Thanks !