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DSP C54x power supply troubles

Delared Delared
Expert 1945 points

Other Parts Discussed in Thread: CCSTUDIO

Hi,

I have a problem in my DSP C54x power supply.

In my board [PCB designed around C5402 DSP]. I have a voltage regulator that delivers CVDD=1.8V and DVDD=3.3V voltages for DSP power supply.

I was able to run/debug programs, but after while, some problem occurred. [unfortunately-as yet- I don’t know what is exactly the source of problem].

anyway, now the main problem is that CVDD and DVDD connections are tied. As a result:

- I can't connect Emulator to the board

- I measured CVDD=DVDD=3.3V.

- when DSP powered, the XF and HRDY signals =3.3V.

- I verified that problems doesnt come from the voltage regulator(now removed from the PCB). 

My questions:  

1. I want to verify if the problem of connection between CVDD and DVDD comes from the DSP itself. It’s possible?

2.  what could happen if the DSP has powered with CVDD=DVDD=3.3V?

your suggestions to solve my problem will be appreciated.

  • 0
    TI__Mastermind 23785 points

    If CVDD is 3.3V, you might have already destroyed the device since CVDD is rated from -0.3V to 2.0V. In order to confirm, first to remove the device and condirm CVDD and DVDD are ok on board without device; then place a new/good VC5402 device and try again.

    Regards.

  • 0 in reply to Steve Tsang
    Expert 1945 points

    Steve,

    I have powered the DSP with 1.8V to 2V (CVDD=DVDD=1.8..2V because CVDD and DVDD still linked) and connected the XDS200 Emulator to the target.

    Result: Test connection succeeded !

    question: view that the JTAG test connection passed OK, it means that my DSP still works ? 

  • 0 in reply to Delared Delared
    TI__Mastermind 23785 points

    If you can connect via CCS, yes, the chip is alive. Try read/write IO registers and memory space, or runs code on it.

    Good luck.

  • 0 in reply to Steve Tsang
    Expert 1945 points

    Steve,

    */ I tried to read/write IO registers without success, I can hardly run/debug code on DSP for a short time using CCStudio/XDS2xx Emulator. we can accept that due to non-normal power supply (CVDD=DVDD=2V).

    */ I tried to run code on it  through HPI bootloader also without success.

    */ I have verified again my board in order to make sure that the power supply issue doesn't come from another component. 

    Excuse me to ask that again, but I want to be sure that: If the test connection of CCStudio/XDS2xx succeeded-->  it means that my DSP [core+peripherals] still works fine without restriction ?

  • 0 in reply to Delared Delared
    TI__Mastermind 23785 points

    The answer is NO. Since CVDD is rated from -0.3V to 2.0V and it has been driven to 3.3V, the chip could be demanded. Thus I suggested to read/write IO registers. Now with your latest finding, the chip is most likely demanded.

    Have you tried first to remove the device and confirm CVDD and DVDD are ok on board without device; CVDD and DVDD have difference ratings. After confirming the board power is ok, then place a known good VC5402 device and try again.

    Regards.