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MMWCAS-DSP-EVM: Profile / Chirp / Frame Configuration

Luca Previati
Prodigy 140 points
Part Number: MMWCAS-DSP-EVM

Tool/software:

I'm trying to setup a Lua script that can help me set some parameters and then complete the device setup from there. In this case, however, I'm not encountering any functional issue, but rather I'm not sure if I understood correctly how they work.

Following the "Programming Chirp Parameters in TI Radar Devices" guide, I think I understood what most of the configurable parameters do, in order to set a particular waveform and so on. In the scripts, though, I always have to set a specific device index (either 1, 2, 4, 8, referring to a particular cascade chip) to properly call the API functions (that's at least what I'm getting from the console log). And, for the Chirp Configuration, at least it makes sense to me: each device is configured with a specific chirp waveform that has to be used from its TX antennas. But I simply don't get what it's supposed to represent for the Profile and Frame configuration.

Could you please help me to understand what's the actual logic behind that? Is it because each cascade chip can have a set of 4 profiles, and a set of at most 512 chirps related to them, and then maybe I can set different frame configurations for each device? Or there's something else I didn't understand? I'm trying to construct some data structures for easier user experience, and I wanted them to be the most intuitive possible - so, I need in first to understand them correctly :)

  • 0
    TI__Genius 11190 points

    Hi Luca,

    Apologies for the delay. I was out of office the previous week. You can refer to the following thread for your query.

    https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1039805/mmwave-dfp-confusion-with-deviceindex-and-devicemap-for-connection-between-awr2243boost-and-raspberry-pi

    Regards,

    Shruti

  • 0 in reply to shruti gupta
    Prodigy 140 points

    I'm sorry, maybe I did not explain myself correctly.

    The problem I'm facing is not related to the device indexing, I already had figured this out by myself and designed my setup scripts around this. My problem is, I don't seem to be able to understand why I need to explicitly assign the ProfileConfig, ChirpConfig and FrameConfig API calls to each device.

    I'm guessing that each device can support 4 different profiles (hence, the radar device index passed to ProfileConfig), 512 chirps derived from these 4 profiles (hence, the radar device index passed to ChirpConfig) and a frame construction based on the chirps defined for that device (hence, the radar device index passed to FrameConfig). But, I'm not at all sure that mmWave Studio is doing this when I'm calling those functions, and I've found no source that guarantees me this (or anything else, for what it matters).

    My question is, am I doing things correctly? Or maybe mmWave Studio is programmed in a different way I didn't understand, and I should change the way I'm setting up things, in order to make my script work in the way I'm intending?

    Besides this, I'm going to ask another question related to the previous one.

    I'm trying to make multiple calls to my DataCapture script (which only triggers a new capture, after the device setup is complete, in order to have multiple data captures in a row to be elaborated in sequence), and I'm strangely noticing that almost every file differs in size from the others (from capture to capture - files related to the same capture have luckily the same size). This, of course, happens every time if I try to make multiple calls to my script, and even if I close mmWave Studio, redo my setup, and launch a new capture.

    And I'm not finding a way to reliably fix this size; for reference, I'm triggering the ar1.TDACaptureCard_StartRecord_mult API call before each data capture, trying to set the number of frames to 0 or to a fixed value (like the help in the Lua Shell suggests), but it doesn't seem to have any effect on the size of my data files. Also, the file size seems to be totally chaotic: sometimes I have files in the order of 500KBs, when other times the size is lower than even 100KBs.

    What's a parameter I can change that affects the file size, and what other parameters I could check in order to find something that's messing up the file size? I really need to be able to fix the file size (hence, the number of measures I'm taking, with a set number of chirps and frames and a fixed setup of TX/RX antennas), and I don't seem to be able to do it.

    Final question I'm going to make on this topic is: what exactly is the Sample Rate (ksps) in the ProfileConfig?

    I'm guessing from the name that it's probably one of the parameters I have to adjust, in order to fix my previous problem, but I have no clue what it's supposed to represent. Isn't mmWave Studio able to automatically detect the sampling frequency for every chirp, when I'm setting up a frame with a set number of chirps inside, each with a set duration determined by the ProfileConfig parameters, in order to have a fixed number of samples for a single measure?

    I really hope that this is something mmWave Studio is doing for itself, without me having to manually calculate the sampling frequency I need to obtain a certain number of full frame captures in a set period of time. Also, if that's going to be the case, what is the ADC Samples going to represent, then?

    Looking forward for a response to my questions. Thanks in advice.