RX pull-up
Posted: Tue May 30, 2017 10:35 pmI wanted to use a simple voltage divider on the RX pin to be compatible with 5v devices but I realised that the internal pull-up of the RX pin is enabled by default and the pull-up resistor value is 100 ohms.
So a simple voltage divider wont work...
Voltage input low (vil) is 0.25v so I need a vert low resistor if I want to create a simple circuit with a 3.3v zener.
Other solution is with a pnp transistor.
Any other ideas (except a level shifter chip).
Thanks
So a simple voltage divider wont work...
Voltage input low (vil) is 0.25v so I need a vert low resistor if I want to create a simple circuit with a 3.3v zener.
Other solution is with a pnp transistor.
Any other ideas (except a level shifter chip).
Thanks