2022-05-10 08:26 AM
I am trying to set up SMPS power Regulator for low power operation. I am using Nucleo-U575ZI-Q board. I set the bit in CR3 register but bit in SVMSR is not being set.
Do anyone have idea what can be wrong? Is there something that I am missing?
2022-05-12 12:31 AM
Hello @nilesh-dryad
Did you enable the RCC->AHB3ENR PWREN (bit 2) before poking the PWR->CR3 REGSEL to 1 ?
Then yes, you you see switch the SVMSR toggling to 1.
BR,
Bruno
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2022-05-12 02:23 AM
@Bruno_ST
Thank you for your quick reply.
I am using the example from STM32CubeIDE for Nucleo-U575 without any change. Am I supposed to change anything in example?
BR,
Nilesh Vora
2022-05-12 03:09 AM
Typically the PWR peripheral is enabled via HAL_Init() and its call to HAL_MspInit() stm32u5xx_hal_msp.c
The SMPS settings via SystemPower_Config()
See example
STM32Cube_FW_U5_V1.1.0\Projects\NUCLEO-U575ZI-Q\Examples\CRC\CRC_Example\Src\main.c
2022-05-12 03:37 AM
I checked Hal_Init function, it is set. Do I need to set any jumper or solder bridge on Nucleo board? I checked the user manual of the nucleo board. I didn't find anything related to SMPS.
2022-05-12 03:44 AM
It is enabled. I checked it. I don't understand why the sample examples are not working on nucleo board.
I also checked TX_LOWPOWER example, it is also not working. Power consumption is always around 60ma. Tickless idle also does not seem to work. I didn't try all the examples.
2022-05-13 12:29 AM
Examples should work straight away without any change on the board.
For Tx_LowPower, LED_GREEN toggles every 500ms for 5 seconds each time user press the user button (consumption ~4/5uA). Something looks wrong on your Nucleo MB1449 board. Consumption under reset ~550uA (black button keep pressed and IDD measure on pin 2 of JP5 means on VDD_MCU side)
Bruno
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2022-05-13 02:57 AM
Strange. I have 3 Nuclen board with me. I tried on two. I didn't work but today I opened the 3rd one and the examples worked on the 3rd one. So the SMPS regulator worked on 3rd one.
2022-05-13 06:52 AM
Yes, strange... as the board is tested in production...
When you say the 2 first boards are not working, the issue is only on SMPS that doesn't start on the board ?
Is the on-board SMPS on JP4 @1.8V ok ?
60mA is so high ! The U575 doesn't consumes so much on LDO @160MHz at 25°C.... (cf datasheet)
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2022-05-13 07:08 AM
If you switch to LDO on those two boards then it works fine.
One more question: Do I need to switch to 1.8V if I enable SMPS power regulator?