RTOS/TMS320F28335: C2000 real time with matlab/simulink / real time resolution problem

s singh

Part Number: TMS320F28335
Other Parts Discussed in Thread: ENERGIA

Tool/software: TI-RTOS

hello
i am using tms320f28335 experimental kit / CCSv6 for real time implementation of MATLAB simulink model.
build, load and run is successful .
But the problem is :

output, as we see in the scope of simulink model is not accurate as that of DSO (digital signal oscilloscope).
I mean the output at the pins of experimantal board is not same as that of scope of simulink model.

Actually the time resolution is not same

waveform of pulses that came in 0.02 sec in simulink scope is actually coming in more that 5 sec on the DSO.

I think dsp processor is taking long time to run the model. In this case real time implementation is not possible.

Please suggest, what can be done

Thanks
satwant

over 7 years ago

0 Gautam Iyer over 7 years ago

Guru 192875 points

Hi Satwant,

Which Matlab version are you using?

Regards,
Gautam

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

hi sir
i am using Matlab 2016a.

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

sir
i am using MATLAB 2016a.

Sir, recently i purchased your ebook " An introduction to texas instruments C2000 real time control microcontrollers ".
i have some queries.
could u please provide your email id.
Thanks

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

satwant singh2 said:
i am using MATLAB 2016a.

I've personally used MATLAB 2016b and I didn't face any such issues. Can you check with the Matlab forum as help over here for Simulink based code generation is very minimal.

Regards,

Gautam

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

Is there any sample time issue.
i am using sample time of 2e-6 and 370e-6 in simulink blocks.

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

re specific info regarding my issue

0 Brian McKay over 7 years ago in reply to s singh

Mastermind 9005 points

Hi Satwant,

You can get better assistance via MathWorks Technical Support, since it was MathWorks to created this solution.

It is possible to create a model that is too computationally intensive to run in real-time on HW. It is also possible that the configuration isn't correct - this is where MathWorks Tech Support can assist.

Cheers,

-Brian

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

sir
As u said, you did not get any such problem(real-time time resolution issue) with Matlab 2016b.
Could u please tell what is the sample time and dsp board u are using in real time simulation with Matlab 2016b.
Actually mathworks are saying that there may be the issue in sample time of 2 microsecond u are using in the model.

Mine processor is tms320f28335.

Thanks.

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

satwant singh2 said:
Could u please tell what is the sample time and dsp board u are using in real time simulation with Matlab 2016b.

I've used All the launchpads with 2016b. More relevant to your case would be Launchpads based on F28377S & F28379D. Do check my youtube channel:

https://www.youtube.com/channel/UC0vWIpaMzxZ0RqT4r4Kp75w

Regards,

Gautam

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

Could u please tell the value of sample time on which u have used these processors in real time simulation .

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

This was pretty slower... ADC sampling was 10ms. Just now I noticed that you were talking about sampling time of 2us... that's really really fast!

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

As u suggested the F278377D and one more processors. they are of 200MHZ.
Is there any processor (launchpad) more than 200 MHz by texas insturments.
And more easy for me is the energia development env. (rather than using CCS) as that is same as that of arduino.

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

satwant singh2 said:
As u suggested the F278377D and one more processors. they are of 200MHZ.

F28379D is what I suggested and not the above part :)

satwant singh2 said:
Is there any processor (launchpad) more than 200 MHz by texas insturments.

Nope! F28379D has C28x core and CLA and both have the operating frequency of 200MHz each. Combined can perform 400MIPS.

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

sir

Does energia supports F28379D.

I m not getting this board in tools>boards>boards manager in energia software pane.

Thanks

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

As of now... NO!

0 s singh over 7 years ago in reply to Brian McKay

Intellectual 360 points

Sir

Actually the problem is in the sample time.

tms320f28335 (150MHZ) is unable to handle real time data having resolution of 2 micro seconds.

As i think, MATLAB/SIMULINK solution is OK but TI should think about the more advanced processors.

Thanks

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

sir

i want to know whether any kind of coding tutorials (using CCS) for texas dsp processors are present on intenet/youtube, so that processor can be full utilized upto its capacity.

Thanks

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

Sir
i am trying EPWM module of f28335 processor using the inbuilt simulink block.
Here we can specify the TBPRD value in seconds for up-down counter.
But for the CMPA and CMPB , value can only be entered in units of clock cycle or percentage.
How can we enter CMPA/CMPB values in seconds.

Can we use both CMPA and CMPB values to control ePWM1A Or CMPA can only be used to control ePWM1A?

Thanks

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

satwant singh2 said:
i want to know whether any kind of coding tutorials (using CCS) for texas dsp processors are present on intenet/youtube, so that processor can be full utilized upto its capacity.

I'm not sure of coding tutorials but you check out the workshop materials:

They're pretty old but can refer.

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

satwant singh2 said:

Can we use both CMPA and CMPB values to control ePWM1A Or CMPA can only be used to control ePWM1A?

CMPA is the duty cycle register in clocks/percentage for ePWMxA module and CMPB for ePWMxB. I hope you got my point!

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

sir

How can i convert the usec. time duration in clock cycles (Any formula for that)?

(dsp28335)

Thanks

0 Gautam Iyer over 7 years ago in reply to s singh

Guru 192875 points

Hi,

Check this video of mine where I configure ePWM module in simulink:

Regards,
Gautam

0 s singh over 7 years ago in reply to Gautam Iyer

Intellectual 360 points

Actually my question is :

i have put 30000 in TBPRD value (in clock units, up-down counter) and i want to know its equivalent time period.
i.e relation between clock units and time.
processor is f28335(150MHZ)

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RTOS/TMS320F28335: C2000 real time with matlab/simulink / real time resolution problem