The idea came from the popular WS2812(B)/Neopixels which are serially interfaced and adressable high brightness RGB LEDs. 7 segment displays normally require one IO pin per LED + one pin for the dot in the corner. That's 8 pins plus one pin for each additional display if you drive them sequentially per display. This method also requires a transistor for each common anode/cathode on the displays plus resistors for each LED segment.

There are other alternative integrated circuits to help drive 7-segment displays like the BCD to 7-segment decoder CDx4HC(T)4511 and the MAX7219/MAX7221 which all both require additional components (in addition to itself), are expensive and some require both additional chip for each new display and also the use of extra IO pins for each new control IC or display.

The mini serially interfacable 7 segment displays have the following features:

• Serial interface

• Daisy chainable with no additional IO pins per display

• No external components

• Addressable by software

• Requires only 2 IO pins (74HCT164 version)

• Surface mount