AM3358: AM3358 Core not locking

MADHU GANDEPALLI

Part Number: AM3358

Hello team,

I have designed a custom board using AM3358.

In one of the boards I have found that processor is not booting.I have checked the UART log and even CCCCC.... was not coming.

So, I tried connecting the board using CCS(Code Composer Studio) and found the following error.

CortxA8: Output: **** AM3358_SK Initialization is in progress ..........
CortxA8: Output: **** AM335x ALL PLL Config for OPP == OPP100 is in progress .........
CortxA8: Output: Input Clock Read from SYSBOOT[15:14]: 24MHz
CortxA8: Output: **** Going to Bypass...
CortxA8: Output: **** Bypassed, changing values...
CortxA8: Output: **** Locking ARM PLL
CortxA8: Output: **** Core Bypassed
CortxA8: Output: **** Now locking Core...

The board is stuck at locking the core.

I have verified the voltages of CAP_VDD_SRAM_CORE,CAP_VDD_SRAM_MPU,CAP_VBB_MPU.

I have also verified the reset oins of processor and processor is not in the Reset mode.

I could sense some voltage is not being properly connected and is causing issue. If i am sensing correct , Kindly help me in identifying the issue and solving it.

Else let me know what could be the issue.

Kindly reply at the earliest.

Regards

Mad_hu

over 4 years ago

0 JJD over 4 years ago

TI__Guru* 86060 points

Mad_hu, it is most likely a problem with the PLL voltage rails. Check section 6.1.4 of the datasheet and ensure all the voltage rails mentioned in table 6-1 are powered correctly

Regards,

James

0 MADHU GANDEPALLI over 4 years ago in reply to JJD

Expert 1300 points

Hello James

Sorry for the delay in response.

Due to the second wave of COVID-19 in INDIA , I cannot access my board now. Will update you shortly after I verify the voltage rails as per table 6-1 of datasheet

Regards

Mad_hu

0 MADHU GANDEPALLI over 4 years ago in reply to JJD

Expert 1300 points

Hello James

Sorry for the delay in response.

Due to the second wave of COVID-19 in INDIA , I cannot access my board now. Will update you shortly after I verify the voltage rails as per table 6-1 of datasheet

Regards

Mad_hu

0 MADHU GANDEPALLI over 4 years ago in reply to JJD

Expert 1300 points

Hello James

Sorry for the delay in response.

Due to the second wave of COVID-19 in INDIA , I cannot access my board now. Will update you shortly after I verify the voltage rails as per table 6-1 of datasheet

Regards

Mad_hu

0 MADHU GANDEPALLI over 4 years ago in reply to JJD

Expert 1300 points

Hello James

Sorry for the delay in response.

Due to the second wave of COVID-19 in INDIA , I cannot access my board now. Will update you shortly after I verify the voltage rails as per table 6-1 of datasheet

Regards

Mad_hu

0 MADHU GANDEPALLI over 4 years ago in reply to JJD

Expert 1300 points

Hello James

I could see that all the voltage rails are as per the datasheet only. I could see the voltages as below:

VDDS_PLL_MPU - 1.8V

VDDS_PLL_CORE_LCD - 1.8V

VDDS_PLL_DDR - 1.8V

VDDA1P8V_USB0 - 1.8V

These voltages are measured across the decoupling capacitors of the rails. The vias are behind the IC only and hence cannot probe them.

Regards

Mad_hu

0 JJD over 4 years ago in reply to MADHU GANDEPALLI

TI__Guru* 86060 points

Mad_hu, ensure to check these voltages for droops while the PLL is being configured and trying to lock. Did you change the GEL scripts at all? Can you post the GEL script you are using?

Regards,

James

0 MADHU GANDEPALLI over 4 years ago in reply to JJD

Expert 1300 points

Hello James,

The voltages are stable.

Kindly find the below attachment for the gel file.

mad.gel

Regards

Mad_hu

0 JJD over 4 years ago in reply to MADHU GANDEPALLI

TI__Guru* 86060 points

I don't see a problem with the GEL that would cause the PLL lock issue. Does this only happen on one board, or multiple boards?

Regards,

James

0 MADHU GANDEPALLI over 4 years ago in reply to JJD

Expert 1300 points

Hello James

This issue is with only one board.

Regards

Mad_hu

0 JJD over 4 years ago in reply to MADHU GANDEPALLI

TI__Guru* 86060 points

Ok, thanks. I think it is most likely some sort of assembly issue with this one board. It might be a power or ground pin not soldered correctly, either on the processor or the power source. It might be difficult to find because of the BGA package. I would double check the power rails, especially for PLL and the OSC, as close to the processor as possible. Otherwise, you may have to reflow the board or replace the processor on that board.

Regards,

James

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AM3358: AM3358 Core not locking