S32K312 reset signal pull down problem

[feiyiniu]

During testing, it was found that when S32K312 was in standby mode and the Reset signal was pulled down 0-25ms, the reset reason obtained was wake-up reset: MCU_ WAKEUP_ REASON.And Reset signal are pulled down for 30ms or more, the reset reason obtained is power on reset: MCU_ POWER_ ON_ RESET. May I ask why this situation occurs？Thanks！

[JackKai]

When using the S32K312 chip, I encountered the following problems. During the entire software OTA process, the data will first be downloaded and verified. After the verification is completed, the Hse area will be cut and the software will be reset. However, occasionally the software cannot be reset and the RST pin of the MCU periodically sends a 50us pull signal at 28ms. Low action.

[JackKai]

I am encountering a problem now. After the software is downloaded and verified, the software will be reset. After the reset is completed, HSE zone switching will be performed. At this time, zone switching exceptions will occasionally occur, causing the current controller to be abnormal. The RST pin will be abnormal with a 28ms cycle after powering on. Pull low.

[danielmartynek]

Hello @feiyiniu,

I understand you use the RTD drivers, which version do you use?

Can you please monitor the power supply of the MCU?

If DES[F_POR] = 1, all reset status in the FES and DES registers must be ignored at power up.

Otherwise, can you read the MC_ME[MODE_STAT] and all the MC_RGM registers at the beginning of main()? 

Thank you,

BR, Daniel

[danielmartynek]

Hello @feiyiniu,

I understand you use the RTD drivers, which version do you use?

Can you please monitor the power supply of the MCU?

If DES[F_POR] = 1, all reset status in the FES and DES registers must be ignored at power up.

Otherwise, can you read the MC_ME[MODE_STAT] and all the MC_RGM registers at the beginning of main()? 

Thank you,

BR, Daniel

[feiyiniu]

My version is S32K3_RTD_2_0_0_D2203_ASR_REL_4_4_REV_0000_20220331;

The MCU is powered on all the time;

The reset cause is power-on reset: (reset pulse width above 30ms)

MC_ME[MODE_STAT] = 0x0000_0000

MC_RGM[DES] = 0x0000_0001

MC_RGM[FES] = 0x0000_0000

MC_RGM[RDSS] = 0x0000_0000

Power_Ip_GetResetReason() obtain the reset source is MCU_POWER_ON_RESET

The reset cause is wake reset: (reset pulse width 0-25ms)

MC_ME[MODE_STAT] = 0x0000_0000

MC_RGM[DES] = 0x0000_0000

MC_RGM[FES] = 0x0000_0001

MC_RGM[RDSS] = 0x0000_0001

Power_Ip_GetResetReason() obtain the reset source is MCU_WAKEUP_REASON

[danielmartynek]

Hi @feiyiniu,

This would be the POR_WDG.

Please have a look at the RM, Chapter 34 Power-on Reset Watchdog (POR_WDG).

Regards,

Daniel

[feiyiniu]

The POR_WDG configuration is valid in standby mode, but invalid in normal mode. It can be understood that the POR_WDG configuration is only available in standby mode?

Thanks!

[danielmartynek]

Hi @feiyiniu,

It depends on the DCF record, but by default it is enabled:

BR, Daniel