LPC55S04 gives bus fault and goes into hard-fault

[KumarG]

I am using LPC55S04 for one of my projects.  Firmware is finalized and is working fine on more than 20 boards.  

Same code when programmed into newly purchased controllers is leading to continuous hard-faults, some times bus-fault is shown while debugging, some times FORCED fault.

Debug window shows different function names every time after halting.

these controllers also has two pin-1 markers (previous controllers had only one). 

Request to please help me to find out the root cause of the issue.

Regards

Kumar

[xiangjun_rong]

Hi,

Pls download SDK package from the website:

https://mcuxpresso.nxp.com/en

try the LED or uart example, check if you have issue.

BTW, pls try to use internal IRC.

BR

XiangJun Rong

[KumarG]

Hi,

I have tested with led_blinky project from SDK package, following are the observations.

1) Code working fine when using 12Mhz FRO clock BOARD_BootClockFRO12M();

2) Code going into hard_fault immediately when using BOARD_BootClockFROHF96M();

3) Code going into hard_fault immediately when using BOARD_BootClockPLL96M();

Regards

Kumar

[xiangjun_rong]

Hi,

Okay, when your board runs up to 96MHz, the hardfault error occurs immediately, I suppose the firmware is correct because you use SDK example.

Maybe your board design has issue, especially the power supply part.

Can you share the power supply schematics of board so that we can have a review?

BR

XiangJun Rong

[KumarG]

Hi,

Please find the schematic of power supply part 

Regards

Kumar

 

[xiangjun_rong]

Hi,

I have checked the schematics, I suppose it is okay.

Pls test the VDD_PMU pin voltage and check if it is the voltage you set in the software.

BTW, do you think that the 3.3V power supply can provide enough current?

BR

XiangJun Rong

[KumarG]

HI,

Voltage at VDD_PMU is 1.076V, programmed is 1.15V (DCDC_POWER_PROFILE_MEDIUM)

3.3V Power supply comes from LM1117-3.3 regulator, which can drive 800mA.

Regards

Kumar

[xiangjun_rong]

Hi,

The VDD_PMU pin voltage does not reach to the expected.

maybe it is related to the inductor type for the DC/DC converter, pls refer to the community ticket.

https://community.nxp.com/t5/LPC-Microcontrollers-Knowledge/why-is-the-spec-of-saturation-current-fo...

It gives the inductor saturation spec required.

Hope it can help you

BR

Xiangjun Rong

[KumarG]

Hi,

Inductor used is SRP2510A-4R7M 

Saturation current rating is 1.8A & rated rms is 1.36A

I have captured voltage before and after inductor, there is a large voltage spike on core voltage.

Regards

Kumar

[xiangjun_rong]

Hi,

The DC/DC voltage delta is very high, I suppose that this is related to the 22uF capacitor.

Pls refer to the 22uF capacitor feature in the AN

https://www.nxp.com.cn/docs/en/application-note/AN12325.pdf

Hope it can help you

BR

XiangJun Rong