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Lagodolio
Associate III
April 23, 2021
Solved

STM32H743 5V tolerant pins for an LQFP176 Package

  • April 23, 2021
  • 2 replies
  • 2216 views

Hello, I have a doubt about the voltage tolerance of STM32H743: looking at Stm32h743bi.pdf, LQFP176 pins are numbered 1,2,...,176, while CubeIDE gives me PA1, PA2, PB1, PB2.... etc.

So, how can know if my UART3 pins (PB10 & PB11, Alternate function Push-Pull, No Pull Up - No Pull-Down, Maximum Output Speed Low) are 5V tolerant, to connect my RS232 to RS485 converter?

Thanks and best regards

This topic has been closed for replies.
Best answer by Tesla DeLorean

Try the Datasheet

0693W00000AMOxQQAX.jpgTypically you'd use a 3.3V CMOS MAX3232 to get RS232 compatible levels.

2 replies

Tesla DeLorean
Tesla DeLoreanBest answer
Guru
April 23, 2021

Try the Datasheet

0693W00000AMOxQQAX.jpgTypically you'd use a 3.3V CMOS MAX3232 to get RS232 compatible levels.

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Lagodolio
LagodolioAuthor
Associate III
April 24, 2021

Hello Tesla DeLorean and thanks for your reply. I didn't notice the "Pin Name (function after reset)" :o column, so I wasn't sure it was 5v tolerant.

In that case, my pins should be 5V tolerant.

I have to connect my stm32 to an RS232 -> RS485 industrial converter. I measure 5V from the TX output of the adapter, but I need only to use the RX line of the converter (linked to the TX line from the micro). Can I damage my STM32? They suggest that the converter should accept also 3.3V signals, but my first problem is to not break the H7.