For a circuit you need to control two LEDs, but unfortunately only one digital output is free. The supply voltage of the microcontroller and the board is 5V. LED1 should have a forward voltage $U_{f,1}=2.3V$ (red), LED2 should have a forward voltage $U_{f,2}=2.1V$ (green).

1. Design a circuit from the existing voltage levels so that both LEDs can be driven.
   Existing voltage levels:
   1. Supply: $5V$
   2. Digital output: $5V$, $0V$ or high impedance

1. Calculate the values for the other necessary components

   
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