Interfacing STM32F205RBT6 to max232

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aamirali

Joined Feb 2, 2012
412
Hi,

Can I interface directly max232 to STM32F205RBT6.
I have given 5V to VCC of max232 & 3.3V to vcc of STM32.

1. In datasheet of max232, it is given that Vih = 2V. So my 3.3V signal from STM32 will serve the purpose of txd

2. In case of rxd, 5V signal will come from max232 to STM32. Are STM32 pins are 5V tolerant in case I configured them for uart?

3. I have place 150ohm resistor each in between txd & rxd connections of both IC.
 

cmartinez

Joined Jan 17, 2007
8,220
Try using the circuit that I've attached for you.
It's a bi-directional level shifter interface, which means that it can be used either way as input or output.
I've been using this circuit for a long time with my designs, and it's worked perfectly for me.
I've also attached a PDF explaining how the circuit works.

Regards, and have lots of fun with your project.
 

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