Bi Color LED using single microcontroller pin

Other Hardware LEDs and Multiplexing
1

I have a bi color Red-Green LED with 3 legs (Common Anode).

How can I drive the LED using a single pin from microcontroller (ATtiny45) without using any external logic gates?

I only need red or green at a time mutually exclusive. Combined color/Off state not needed. They are just for status indicators and need to be as bright as possible.

Any schematic using discrete components would be helpful.

Thanks

2

I think you can do this with one extra part (N-channel logic mosfet). A 2N7000 will do.

Use a 220ohm current limiting resistor between +5volt and LED anode.

MCU output pin to GREEN cathode and mosfet gate.
Source to ground.
Drain to RED cathode.
Leo..

3

Much simpler would be if you wanted yellow as one of your colours. Then just have one LED on all the time and wire the other one to be controlled by the Arduino.