STPMIC1 BUCK2 VDD DDR

[foc]

Hello everyone,
I designed a board using the STM32MP157 and STPMIC1A. During the initial power-on tests, I noticed that there was no output from the VDD BUCK.
The board was tested without any operating system or boot process. Is this normal? This is the first board I’ve designed with the STM32MP1, and if this is normal, I can proceed with porting the OS however, if it’s abnormal, I’ll need to investigate the source of the problem. The board was also successfully detected by the PC in USB boot mode.

 

Regards

[Olivier GALLIEN]

Hi ​@foc,

Please refer to STM32MP151/153/157 MPU lines and STPMIC1 integration on a wall adapter supply - Application note to have a clear idea how bundle STM32MP157 and STPMIC1A might behave. 

Indeed VDD might automatically start at boot. 

Olivier 

[foc]

Hi Olivier,

Thanks for your reply.

I saw this sentence: The STPMIC1APQR does not start VDD_DDR, VREF_DDR and VTT_DDR at power up. They must be powered up and powered down by STM32MP15x software, respectively at STM32MP15x boot up and shutdown.

I had checked it, but I didn't pay close attention. This is my first time working with STM32 MPUs, so I don't have much experience, sorry about that.

Regards

[Olivier GALLIEN]

Hi ​@foc 

You didn’t precise VDD DDR so I assume VDDIO 😊

Glad that the AN provide you the required guidance. 

Olivier