How to change VOS bits in 32L0xx

[Zoran Daric]

Posted on January 25, 2017 at 08:19

Hi,

According to reference manual RM0377 (page 138 6.1.5 Dynamic voltage scaling configuration)  programming voltage regulator is very easy. Unfortunately I'm not able to do this on two Nucleo demo boards with STM32L031 and STM32L053 MCUs. After writing a new value to VOS bits in PWR_CR register, I read always the same value 1.5V (range 2). Is there any other condition, except power supply, that has influence on this? Please help me to solw this problem.

Regards

#stm32l0-voltage-scaling

[Nesrine M_O]

Posted on January 26, 2017 at 10:23

Hi,

An embedded linear voltage regulator supplies all the digital circuitries except for the Standby circuitry. The regulator output voltage (VCORE) can be programmed by software to three different ranges:

• Range 1 (VDD range limited to 1.71-3.6 V), with the CPU running at up to 32 MHz

• Range 2 (full VDD range), with a maximum CPU frequency of 16 MHz

• Range 3 (full VDD range), with a maximum CPU frequency limited to 4.2 MHz

To have more idea about system power configuration, I recommend you to start with PWR examples under the STM32L0 firmware package:

STM32Cube_FW_L0_V1.8.0\Projects\STM32L031K6-Nucleo\Examples\PWR

-Nesrine-

[Zoran Daric]

Posted on January 26, 2017 at 11:23

 ,

 ,

Hi

Unfortunately this does not help me. I have system that does not go

to Standby mode, supply is 3,3V and frequency is 525kHz or 4,2MHz.

According to documentation this should work but...

STM32L031 we intend to use in new project for Smart-Home system.

Plan is to produce minimum 10,000 devices in first year. Do you have

somebody who knows this problem and is able to help me?

I was not able to find recommended packet.

Regards

Zoran

W dniu 2017-01-26 o 10:25, Nesrine M pisze:

>,

STMicroelectronics Community

<,https://community.st.com/?et=watches.email.thread>,

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Re: How to change VOS bits in 32L0xx

reply from Nesrine M

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in /STM32 MCUs Forum/ - View the full discussion

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[Nesrine M_O]

Posted on January 26, 2017 at 11:53

Hi,

• Have you try this example: STM32Cube_FW_L0_V1.8.0\Projects\STM32L031K6-Nucleo\Examples\PWR\PWR_STANDBY with no success?
• Could you please precise if you are using a custom board or an ST board?
• Could you please provide more explanation on your case, so that it will be easier to understand the issue?

-Nesrine-

[Nesrine M_O]

Posted on February 01, 2017 at 10:15

To be able to write to PWR registers, you have first to enable PWR's clock by setting RCC_APB1ENR.PWREN.

With the ADC problem, please start a new thread.

+1

-Nesrine-