CCS/TMS320F28027: Low level on XRS pin

rajat devagiri

Tool/software: Code Composer Studio

Hi, i m getting a low level signal on the XRS pin, i checked Vdd voltages it is within the range, i m having decoupling capacitors connected to VDD pins. The low level is a continuous low signal and not a oscillating one,

kindly,help me resolve the issue.I have attached the screenshot of the error

over 7 years ago

0 Hareesh Janakiraman over 7 years ago

TI__Guru* 95315 points

You mentioned in the other post that it is working now, but refer to the same issue (-XRS low) in this post. If the –XRS is indeed permanently low, a CCS screenshot is not useful. Please send the schematics of your hardware.

0 rajat devagiri over 7 years ago in reply to Hareesh Janakiraman

Intellectual 440 points

Hi sir,

yes we were able to bring it out of reset, it was due to 3.3V on VDD pin, which was causing the microcontroller to go into brown out state, there we isolated the 3.3V on VDD pin 43. Shown in aatchment

It was working fine, after sometime when card was in operation, the same issue popped up, can you please point out the possible reasons for low XRSn .......is the microcontroller not operational??

0 Hareesh Janakiraman over 7 years ago in reply to rajat devagiri

TI__Guru* 95315 points

-XRS pin can be either

Permanently High (normal operation).
or Driven low either by an external circuit (the external circuit could conceivably hold the –XRS pin low in perpetuity).
or Pulsed low by the internal WD. The keyword here is “pulsed”. Under no circumstances should you see the –XRS pin permanently low.

Is this the same device that had an incorrect Vdd connection before? If so, it is conceivable that the device is damaged.

0 rajat devagiri over 7 years ago in reply to Hareesh Janakiraman

Intellectual 440 points

thank you, i replaced the device ,it started to work

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CCS/TMS320F28027: Low level on XRS pin