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CHARLIEPLEXING

Charlieplexing is a technique for driving a multiplexed display in which relatively few I/O pins on a microcontroller are used e.g. to drive an array of LEDs.

CHARLIEPLEXING​

Charlieplexing is a technique used to drive multiplexed display using the tri state logic of a microcontroller.

SCHEMATIC​

Charlieplexing vs Multiplexing?​

Problems with Charlieplexing:

  • Requirement of tri state logic
  • Refresh rate
  • Cannot be used to drive higher number of LEDs
  • Cannot use LEDs with different forward voltages

Exercise​

  • Based on the Analog Input change the number of LED which turns on

HARDWARE​

SOFTWARE​