Hi,
when the supply voltage is 3.3V, the MCU is not 5V tolerant even if a pin is configured as open drain. The datasheet explicitly states that open drain pin must be pulled to VDD. And Vih spec says that input voltage can't exceed VDD+0.3V. If an external circuit requires 5V, the only options are either to use 5V supply voltage for MCU or use some voltage level translator.
Regards,
Lukas
Hi,
when the supply voltage is 3.3V, the MCU is not 5V tolerant even if a pin is configured as open drain. The datasheet explicitly states that open drain pin must be pulled to VDD. And Vih spec says that input voltage can't exceed VDD+0.3V. If an external circuit requires 5V, the only options are either to use 5V supply voltage for MCU or use some voltage level translator.
Regards,
Lukas