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CCS/RF430FRL152HEVM: VDD2X in demo software

michael yee
Prodigy 100 points
Part Number: RF430FRL152HEVM
Other Parts Discussed in Thread: PCA9306

Tool/software: Code Composer Studio

We are trying to use VDD2X to power an I2C device. I understand that we will need to control the RFPMM register (EN_V_DOUB).

On the RF430FRL152HEVM w have noticed that VDD2X goes is at 1.35V between "inventory" commands while using RFIDread Win 7.exe. What causes this behavior? (where is the code in the demo software that causes this behavior?)

  • 0
    TI__Expert 7820 points

    The part will automatically power-up VDD2X if there is MCU activity.  During inactive times, VDD2X will be low.

    To continually power VDD2X, EN_V_DOUB must be set.

  • 0 in reply to Alex K.
    Prodigy 100 points

    Alex, Thank you for your reply. BTW, I'm working with Ken Ward at Mizuho on his RFID project. Things are going well.

    This is a related question: I am trying to copy the I2C section of the RF430FRL152HEVM onto our board. I have the EVM in scavenged power mode. I do not see any voltage on the POWER_1V5 net. This is connected to the PCA9306 (I2C translator). I also do not see an voltage on POWER_3V3. I do not see on the schematic a way for these voltages to be supplied when harvesting RF power. I do see about 1.3V on VDD2X (I'm sure the doubler is not on).  The EVM is responding to the RFIDread Win 7.

    Thank you,

    Mike

  • 0 in reply to michael yee
    TI__Expert 7820 points
    The RF430FRL1152HEVM was not designed to be totally power by RF scavenged energy - mainly only the device and not the I2C/SPI level translators.

    The IC1 LDO is most likely interfering with any RF harvested voltage output on POWER_1V5.

    The PCA9306 1.5V side should be connected to VDDSW. The S6 switch should be in the "Battery" setting to avoid the LDO.

    If you need a 3V supply, VDD2X is one choice but it may not be the best choice for an I2C translator due to limited current output (90uA).