Pull-up Resistor

[thevien2507]

To establish I2C communication between two CH32V003 microcontrollers, do I need to add external pull-up resistors to the SDA and SCL lines, or do the microcontrollers have internal pull-ups?

[maxint-rd]

In my experience: Yes. You definitely need one set off pull-up resistors on the I2C bus.
In my I2C experiements I used two 10k resistors. If there are internal pull-ups, they are not enabled hy default and I have not (yet) found the way.