Is STM32L431KBU6 available in 5V supply? We want to just changed existing part with 5V so that can avoid level shifting of SPI signals(Work on 5V).

[NDesh.2]

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[Michal Dudka]

As far as i know, there is none 5V STM32. But most of STM32 have 5V tolerant inputs. That means you can connect external 5V signals directly to STM pin. You can also transmit 5V signals by "open drain" GPIO output mode with external pullup to 5V, but speed wil be limited (depending on pullup value and wiring capacity).

[NDesh.2]

Thanks for your response.

Actually I want to drive SPI slave from STM32 uC (Master) .This STM32L431KBU6 works on 3.3V & Slave circuit works on 5V.To avoid money in level shifter IC for this I was just looking for same uC specification with just supply voltage 5V.

As you suggested I know for MISO signal this will be easily done but for all other three lines(CS,SCK,MOSI) by just pull up is it possible to do that?

[Michal Dudka]

It depends on communication speed and trace lengths. Generally it is possible. But communication speed is limited on short distances (few centimeters) to typicaly hunderds of kbit/s. Simply look into datasheet and find some "5V tolerant pin". Connect wire same length like you plan to use and pullup to 5V - start with 1kOhm for example. Init it as "Open drain" then toggle with that pin, and look on oscilloscope at rising and falling edge durations. Then you can estimate achievable birates. Then you can possibly decrease pullup value to reach faster edges and higher bitrates. But pullup value is limited into minimal value about 5V/20mA=270R and in that case, communication can take significat total current (3 signals, 20mA each). It's better to hold on values in range 1k or higher if it is possible. And of course, in meantime between communication, you should keep output pins in High to conserve power.

[Andrew Neil]

@NDesh.2​  -What does the datasheet tell you?

@Michal Dudka​ "most of STM32 have 5V tolerant inputs"

To be more precise, most STM32 have some 5V-tolerant pins.

Again, full details will be in the datasheet.

[NDesh.2]

In datasheet it is mentioned as 3.3V or max 3.6V.

But as my product is ready & SW is ready with STM32L431KBU6 uC, just as cost saving view (Remove level shifter IC) & to have all IC's on same voltage(+5V), I am looking for same uC with only supply working voltage as +5V.

I was asking this because generally manufacture like ATMEL produces same uC with variants who works on 3.3V & 5V.

[Andrew Neil]

@NDesh.2​ "generally manufacture like ATMEL produces same uC with variants who works on 3.3V & 5V"

Actually, they don't - very few manufacturers have 5V Cortex-M microcontrollers.

IIRC, Microchip (formerly Atmel) has only one?

EDIT:

[KnarfB]

There is no chip variant, but you can read all about 5V tolerant GPIO in AN4899 Application note "STM32 microcontroller GPIO hardware settings and low-power consumption"

hth

KnarfB

[Andrew Neil]

Have you tried the "STM32 Finder new mobile app" ?

https://www.st.com/en/microcontrollers-microprocessors/stm32-32-bit-arm-cortex-mcus.html#st-highlight-promotion

EDIT

Or the Product Selector?

 

Although that seems to be broken at the moment:

[Amel NASRI]

Hi @Andrew Neil​ ,

Do you still have the issue with "MCU portfolio and selection" please?

There is no such issue on my side.

-Amel

[Andrew Neil]

@Amel NASRI​ - seems to be OK now.

@NDesh.2​ - did it work for you?

[NDesh.2]

Thanks All for your support!!!

[Andrew Neil]

You're e welcome. Please help the community by marking the solution: