STM32F2, 5V open drain pin

[vindhyachal]

Posted on April 23, 2015 at 14:56

1. I am using stm32f205.

2. MCU is powered by 3.3V.3. Another ic pin is driven by 5V logic or (Vih = 0.7*VDD = 3.5V)4. Can I set pin of STM32F2 as open drain & connect 5V by pull up to it.5. Datasheet of MCU says that they are not true open drain pins.

[Tesla DeLorean]

Posted on April 24, 2015 at 03:03

You've enumerated some points, was there a question?

The Open-Drain mode only enables one transistor, the one that clamps to ground. In the high output mode the pin floats, to whatever supply you pull it too, the current will be limited by the resistor. This may also create a potential divider where the output high voltage is less than 5V.