Powering up stm32

[Nidhal Abidi]

Posted on April 17, 2018 at 17:43

which is best to power up    ''' STM32VLDISCOVERY '''   via 5V pins and a ground or 3,3V ???

also which is best to for Digital Input for STM32VLDISCOVERY, using 5v or 3,3V ???

In the data sheet I found that bouth of them works. And when I tryed it, bouth works but in the data sheet reset button and pin PA0(user button) are related to 3,3V.

so wich is the best chice for an industrial

project ???

[Andrew Neil]

Posted on April 17, 2018 at 19:07

What do you mean, 'best' ?

As you can clearly see from the schematics, the STM32 itself is running from 3V - so the only difference between powering the board from 3V or 5V is whether or not it goes through the regulator first.

Check the datasheet for details of the '5V tolerant' pins.

Also check the datasheet for details of the logic thresholds, but I think you'll find this is set by the STM32's supply voltage (3V) - so you gain no advantage from 5V logic levels.

undestrial

You mean, 'industrial' ?

Note that the Discovery boards are supplied by ST as an evaluation tool - they are not intended as final products, and the licence terms specifically prohibit such use.

[Nidhal Abidi]

Posted on April 18, 2018 at 11:57

Thanks, mmm, what if I power up the stm with 5v and then use the stm's 3.3v out as inputs for the switches, or buttons or whatever ???

[Andrew Neil]

Posted on April 18, 2018 at 12:21

Nidhal Abidi wrote:

 what if I power up the stm with 5v

Have you actually looked at the datasheet for the STM32 chip?

It tells you what range of voltages can be used to 'power-up' the chip ...

[Nidhal Abidi]

Posted on April 19, 2018 at 09:37

Great thanks.