In software approach to CPU has to look after digit selection in synchronosim with the data for specific digit. In other words, CPU has to give digit data on one port and then the digit selection bit pattern on the other port in synchronism. The process of refreshing has to be repeated all the time which puts an additional burden on the CPU. This is a major disadvantage of the software multiplexing. Another advantage is that, if CPU gets involved in going some lengthy task which cannot be interrupted to refresh the display, only one digit of the display will be left.

An alternate approach to interface multiplexed displays to microprocessor systems is to use a dedicated keyboard and display controller 8279 , designed by Intel. IC 8279 independently keeps display refresh and scans the matrix keyboard.