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TMS320C6745: Boot problem about Reset-pin

Guru 10235 points
Part Number: TMS320C6745

Hello, TI Experts,

 

Our customer sent us an question about reset of TMS320C6745DPTP3(QFP-pkg).

They found to fail booting in 11 boards of total 1200 boards.

- After they moved 0.1uF capacitor to near RESET-pin following the wiki, they found to success booting.

   http://processors.wiki.ti.com/index.php/OMAP-L13x_/_C674x_/_AM1x_Schematic_Review_Checklist#General_Recommendations

   The wiki said "A useful tip is to place a 0.1uF cap near the reset pin to help avoid ESD-induced resets."

 

- They also tried to probe the RESET-pin by oscilloscope to 11 NG-boards.

   But they cannot see fail-waveform.

   Because the 11 NG-boards success to boot when oscilloscope probe touched to Reset-pin.

 

Question:

    - Are there same experience?    

 

Their assumption is "Reset-waveform captured some noise from next OSC related pin is improved by moving 0.1uF capacitor to near RESET-pin" like below.

  

If there are any comment, please tell us.

 

Best regards,

  • Hi,

    The scope probe introduces some capacitance on the reset line, and when you probe near the DSP it is enough to get the device booting. Their assumption "Reset-waveform captured some noise from next OSC related pin is improved by moving 0.1uF capacitor to near RESET-pin" is correct.

    Please follow the Datasheet & Wiki recommendations.

    Best Regards,
    Yordan
  • Hi,

     

    Thank you very much for your kindness.

    I really appreciate your help.

     

    I'd like to send the answer to the customer.

    Best regards,