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TMS320C6415T-1000 timer timing 8P

TobyM
Genius 5200 points
Other Parts Discussed in Thread: OMAP-L138, AM1808

Hi

looking at the datasheet for this device http://focus.ti.com/lit/ds/sprs226m/sprs226m.pdf

page 131 seems to indicate that the timer speed is the system clock reduced by a factor of 8, is that correct?

 

I am trying to find a device that will give me a wide range of frequencies for us in PWM from 0.1MHz to 50MHz with a high resolution duty cycle over those frequencies which will require timers running close to 1GHz. If my above assumption is correct is there a device anyone can recommend that will give me these timer timings or PWM capabilities?This is the main requirement of any device for this, other requirements are secondary to this only.

 

Thanks

  • 0
    TI__Guru* 84110 points

    Toby Mole,

    Table 1 on page 6 and Figure  6 on page 67 confirm your assumption on the timer's clock speed. Page 131 tells you that an external clock source can be no more than CPU/16.

    What you need is the HRPWM or eHRPWM module found in many of our newer DSPs. I think it was the C2000 family where we first introduced this specialized peripheral with the HRPWM, at least it is the first place I saw it used. Then the eHRPWM has been included with several of our devices.

    The Enhanced High-Resolution Pulse Width Modulation (eHRPWM) module can give you PWM resolution down to 200ps !

    The C6748 is one of the family of devices that offers this peripheral module. It does not give you the 1GHz DSP speed but does run at up to 456MHz and includes native floating point performance. The architectural improvements over the C64x (no +) DSP core that was in the C6415T could give you back most of the performance due to core improvements and internal bus improvements and external memory speeds.

    Or you can add an ARM core to the C6748 and it becomes the OMAP-L138. Now you get the eHRPWM modules plus two cores that are both running at 456MHz, one for the tough DSP algorithm code and one for the interface and control code.

    There is also an ARM-only version, the AM1808.

    Sometimes, we have too many choices. These three are all good potential solutions for you. And I believe they are all pin-for-pin compatible, so you could design with the C6748 and if you later find you need to add the ARM for some extra horsepower, you can do that easily for a small price adder without redesigning your board. Or if you decide the DSP has a lot more than you need, you can save some money by moving to the ARM-only AM1808 or one of the lower priced C6746 or C6742.

    Regards,
    RandyP

     

    If you need more help, please reply back. If this answers the question, please click  Verify Answer  , below.

  • 0 in reply to RandyP
    Genius 5200 points

    Hi Randy

    Thanks for getting back to me with the suggestions, I will def take a closer look at the options you mentioned. I had it in my head that these should work for me but the ePWM and HRPWM guides overloaded my poor little noggin, and I just wasnt sure, will take a closer look when I get back to the office on tuesday and let you know how i get on.

    Thanks again :)

  • 0 in reply to TobyM
    TI__Guru* 84110 points

    Toby Mole,

    Please do three things for me:

    1. Mark one of these posts with Verify Answer to close out this thread with its C6415T timer question.
    2. If you have additional questions about the eHRPWM module on one of the chips, please post a new thread with a descriptive title and your new questions.
    3. Come back to this thread and post a reply with a link you your new thread. That way I will see an email about it, since I am not always monitoring all of the forums.

    Regards,
    RandyP