Increase efficiency in embedded digital-I/O lines

摘要

Digital-I/O-multiplexing techniques, such as "Charlieplexing" or "Gugaplexing," let an eight-digit, seven-segment LED display connect to nine I/O pins of a microcontroller (references 1 and 2). These methods use lower-duty-cycle timing, which requires a driver between the microcontroller's I/O lines and the display to achieve good visibility. The circuit in Figure 1