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N2HET and TMS570LS0432

Thomas Varghese
Prodigy 150 points
Other Parts Discussed in Thread: TMS570LS0432, HALCOGEN

Hello,

I"m trying to set up a TMS570LS0432 with the N2HET block.  I installed the HET IDE and noticed that the chip that I need is not listed.  Am I missing something?  Is there another chip that could stand in for the one I need?

Another question I have is that I want two outputs from this block:

1) N2HET[0] : 4 to 8MHz square wave, should be simple i would think.

2) N2HET[22] 8bit or higher resolution programmable PWM with a 10mSec period, I know this is really slow, perhaps too slow?  If so, I think it can be a be higher, perhaps 1mSec period, but not any higher than that.  This is for backlight LED control.

Let me know anyone can help with this.

Thank you.

--Tom V.

  • 0
    TI__Guru 59540 points
    Hello Thomas,

    I've forwarded your post to one of our N2HET and HET IDE experts. They should get back with you shortly.
  • 0 in reply to Chuck Davenport
    TI__Guru 68920 points

    Thomas,

    We're working on getting all the devices listed in the IDE but this is something that you can also do for yourself.  The '0432 uses the N2HET and has 128 words of N2HET memory,  so you can create a device configuration for that combination by using the menu Tools->Device Configuration and checking the boxes as below:

    What I did was start by doing 'SaveAs' and saved one of the existing configs as MY_0432.   Then checked the boxes as they should be for the 0432 and saved again.

    When you exit the IDE and restart it'll show up in the list when you select "New Project".

    I went and unchecked the boxes of the pins that are not there on the 0432 100PZ pkg but you don't really have to do this - you can leave all 32 and just avoid using the pins in your HET program that aren't going to be available on silicon.

    Best Regards,

    Anthony

  • 0 in reply to Anthony F. Seely
    Prodigy 150 points
    Great! That worked. Thanks Anthony.

    I'm trying to create a system that has a fixed 4-8MHz clock on one pin and a variable duty cycle PWM on another. Could you point me at some examples of how to do this? Not sure where to start.

    --Tom V.
  • 0 in reply to Anthony F. Seely
    TI__Guru 68920 points
    Tom,

    For 8MHz I'd recommend using the ECLK pin. It's a bit fast for N2HET. N2HET running at 80MHz can only execute 5 instructions every 16Mhz (1 loop to set the pin, 1 to clear the pin - to get 8MHz). You'd really be limiting your use of N2HET if you try to do the 8MHz output with it. It's good at making a large # of pins toggle in the 'us' time scale.

    For 10ms no problem. The HET program that ships w. HalCoGen only runs at loop resolution for the PWMs but that still would give you 12.5 bits resolution if the loop resolution is 128 clocks (1.6us). You can get resolution down to 1.25ns by changing out the PWCNT instruction in the HalCoGen program with a hi-res ECMP but for this you'll need to learn the HET IDE and maybe you want to come back to this.

    Best Regards,
    -Anthony
  • 0 in reply to Anthony F. Seely
    Prodigy 150 points
    Hi Anthony,

    While I have your attention: is it possible to have five different PWM outputs with different duty cycles coming of the HET? That is what I really need, but I can do it in software if absolutely necessary.

    Thanks!

    --Tom
  • 0 in reply to Thomas Varghese
    TI__Guru 68920 points
    Absolutely assuming they are slower than say 500KHz - 1MHz.

    The example HET program that comes w. HalCoGen can do this for you. It should be able to generate up to 8 simple PWMs like this. There are some limitations to the program but you can get started and if you hit a block it's easy enough to modify the HET program to do what you want. We have a free HET IDE that can simulate your program and show you waveforms of it executing too.