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Original question:

TMS320F28335: adc initilization fail , during cold booting(without jtag emulation) of 28335

TMS320F28335: When I use the epwm function of 28335, I want to align the epwm clocks of multiple DSPs. Is there any method.

Links
Genius 11540 points
Part Number: TMS320F28335
Other Parts Discussed in Thread: ADS8320, , TMS320F28379D

Hi Team


When the SYNCI function is triggered, the count TBCTR of EPWM of multiple DSP chips is cleared at the same time, but the increase speed of TBCTR count of each DSP is slightly different.
My question is there a way to synchronize theTBCTR of multiple DSPs and increase the clock frequency.

Best Regards,
William

  • 0
    TI__Genius 11540 points

    Actually, the reason I asked that question yesterday is that I want a more accurate result in ADC function.

    As a backup plan,I want to know : Is there any difference between TMS320F28335+ADS8320 and TMS320F28379D 's "16 bit Analog-to-Digital Converter" on Servo Moter? Whether the TMS320F28379D 's 16bit AD result is accurate enough, I don’t need to install other AD chips,like ADS8320 or AD7686(ANALOG DEVICE). which plan is better? TMS320F28335+ADS8320 or single chip TMS320F28379D.

    I think if I control ADC time I will get better result, that 's why I want all DSPs I use is at a same CLK. So I asked the question yesterday. Actually, What I want all is just better AD result

  • 0 in reply to Links
    TI__Mastermind 42195 points

    Jiahui,

    The sync frequency of the sync source chip effectively becomes the frequency of any sync destination device which has a slower frequency. This is because the slower sync destination are always advanced to the frequency of the sync source. If the sync destination device's frequency is faster than the sync signal then this behavior is lost.

    The amount of increase in clock frequency is dependent on how fast the sync signal is and what frequency the sync destination device is configured for.

    You can align your ADC reads with your PWM outputs. Candidly we have hundreds of customers using F28379D(and f28335) in servo motor applications. 

    Please note that the quality of your ADC reads is dependent on the layout of your hardware, are you using custom hardware? The accuracy is also dependent on when the ADC samples are taken.

    Regards,
    Cody