Hello,
I've completed my evaluation of the LDC eval board by itself and have moved on to the next stage of development using my own uC, so I've had to write a very basic SPI driver to communicate with the chip. I used my microcontroller with the break-away portion of the LDC eval module (so I'm using the LDC1000 portion and the sensor coil that came with the module originally) and used the SPI driver code I wrote, and successfully was able to read both proximity and frequency data with it and everything seemed fine.
The next step was to use a custom PCB with my uC, the LDC chip and a "custom" sensor coil (that was generated from the WEBBENCH design). This is where my problem comes in. I'm using the same extended SPI transaction to retrieve proximity and frequency data but the frequency data always comes back as all 0's. Proximity data is ok, I move a piece of metal near the target and the count increases. I've followed the directions on the datasheet in terms of how to set the filter capacitor, minimum resonating freq. My coil is supposedly 18.4uH and tank capacitor is 330pF. I have RP_MIN at 0x3F and RP_MAX at 0x00 for now until I can resolve this issue and fine tune them.
The question is, what situation could arise (perhaps from configuring the device incorrectly) that would produce no frequency data? I'm assuming that my SPI commands are ok, since I've used it successfully before, and I verified what the MISO line with an o-scope.
Thank you
