The time consuming of SMO algorithm

dfde jiems

Intellectual 510 points

Other Parts Discussed in Thread: TMS320F28020

hello,

I am using TMS320F28020 and drivering PMSM,

then I find that my pwm interrupt is 100us@40MHz,but in fact:

VOLT_MACRO(volt1)

SMO_MACRO(smo1)

SE_MACRO(speed3)

SVGEN_MACRO(svgen_dq1)

The time consuming of algorithm is about 150us(Add Test Point and use oscilloscope),I do not know why?

and other code is 80us,so total time consuming is 100us + 150us + 80us = 330us

over 10 years ago

0 Gautam Iyer over 10 years ago

Guru 192875 points

Hi,

Is the code executing from flash or ram?

Regards,

Gautam

0 dfde jiems over 10 years ago in reply to Gautam Iyer

Intellectual 510 points

thanks Gautam,

executing from flash in debug mode!

0 Gautam Iyer over 10 years ago in reply to dfde jiems

Guru 192875 points

Can you check the same with RAM? This would give us an idea; what might be the issue.

Regards,

Gautam

0 dfde jiems over 10 years ago in reply to Gautam Iyer

Intellectual 510 points

thanks Gautam，

TMS320F28020 RAM is 3K ， flash is16K ，my code about 6k

in addition ,I donot know how to put the code in RAM?

SO would you tell me What are some of the reasons?

0 Gautam Iyer over 10 years ago in reply to dfde jiems

Guru 192875 points

Here is what you can try for accelerating the execution:

Copy the time critical sections of your code from flash to ram and then execute. This will help you reduce the timings; for more info refer this doc:

3681.Flash to RAM.pdf

Regards,

Gautam

0 dfde jiems over 10 years ago in reply to Gautam Iyer

Intellectual 510 points

thanks Gautam,

I will try your suggestion.

After the test I will tell you the result.

0 Gautam Iyer over 10 years ago in reply to dfde jiems

Guru 192875 points

Sure, sure do keep us informed.

Regards,

Gautam

0 dfde jiems over 10 years ago in reply to Gautam Iyer

Intellectual 510 points

Hi ，Gautam：

in order to test the time-consuming of SMO_MACRO():

if SMO_MACRO()runned in flash ,it consumes 86us.

Then,I have copyed SMO_MACRO() to RAM，it consumes 53us

Is it normal?

0 Gautam Iyer over 10 years ago in reply to dfde jiems

Guru 192875 points

Is it normal?

Yup, this is the expected behavior.

0 dfde jiems over 10 years ago in reply to Gautam Iyer

Intellectual 510 points

thank you very much!

Gautam.

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The time consuming of SMO algorithm