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RF430CL330H: RF430CL330H unpowered operation

Hendrix
Intellectual 1610 points
Part Number: RF430CL330H

I've been testing the RF430CL330H in an unpowered configuration.  With just the RF430CL330H EVM and no MCU attached, I cannot read and write it.   With an MCU attached (also unpowered, and with VCC connected to RF430CL330H) I can read and write it.

Does the RF430CL330H require configuration by an MCU before it can allow reading or writing from an external NFC device?  If so, what exactly has to be set up?  Is it just the RF enable, or are there other registers that need to be set?

Is a reset of the RF430CL330H required?  Using the example code from sloc303, it doesn't work if I remove the reset.  

While the unpowered operation seems to work using just EVMs, I’m concerned with how this will work in a larger system.   The RF430CL330H is waking up and suppling VCC to the MCU, which allows it to wake up and run.   But if this VCC rail is connected to other components, the RF430CL330H will not be able to supply enough power to the rest of the system, and the R/W will not work.   Do we need to isolate the power to the MCU+NFC so that only that part of the circuit powers up?   

  • 0
    TI__Guru*** 131450 points
    Hello Hendrix,

    The RF enable is required for any NFC communication to occur. As far as other settings, there are errata items for the RF430CL330H which should be applied when the device is first configured, or else there is risk that the errata will impact the device.

    Resetting the RF430CL330H may be required if the device is an unknown/bad state such as if it is affected by the RF_LOCK errata item.

    Regarding the application specifically, if you are planning to use RF power to supply the RF430CL330H and there is concern it would source other devices with power then yes isolating the RF430 and MCU would be a good idea.

    Ultimately, while although when loaded with NFC data and the RF Enable is set the RF430CL330H can act as a 'black box' system without need for MCU control in order to send data over NFC, that doesn't mean it is a standalone device so it can't just be disconnected entirely from an MCU.