The high accuracy lab does not have the ability to read calibration data from flash, so it performs a full calibration on each power up. That is very costly in terms of power consumption, and higher than we can tolerate for a loop-powered device and a reasonable cycle rate. The level sense demo can perform a full calibration, store it to flash, and then read it back on later power ups, thereby saving power, but it does not have the accuracy required for our application.
I tried adding the second FFT from the high accuracy lab to the level sense demo, but the resultant level reading was not correct. I suspect that the second FFT reads data from a different memory location that the rest of the level sense demo uses, or the differences between the basic radar configuration of the two labs creates the incorrect reading. In other words, simply adding the second FFT does not work.
I also tried changing the data path configuration from the original level sense values to those from the high accuracy lab. (For instance, the level sense demo defines both a ping and a pong, but the high accuracy lab only has a ping definition. That's confusing as the header to the high accuracy lab's main.c file talks about both ping and pong processing. That header text also references some diagrams which are not present in the file, consequently the header notes are of limited utility.) The file builds and the firmware runs, but there is no apparent measurement made either for the three distance readings from the level sense demo portion or from the second FFT.
Is there any documentation that would provide clear guidance as to how to get the second FFT properly incorporated into the level sense demo? If not, is there detailed documentation as to how the system works, how to set up the firmware for various modes, and meaning of the various parameters? The Radar Hardware Accelerator manual gives a more theoretical description of the capabilities of the device, but not at a level that is readily translatable to firmware code.
Alternatively, is there an existing project that is similar to the level sense demo but has the second FFT to produce a higher accuracy distance measurement?
Thanks,
Alan
