I pulled this old 7-segment display out of storage so I could write a module to control it with FlashForth. Here is the repository URL:
Using the words in
max7219cmd.fs you can control the digits, using either BCD, or controlling the segments individually. Using BCD make your programming much simpler but only gives you four letters to work with (besides the number characters).
I used individual segment control to make this simple demo which lights up each segment in sequence. Here is a video — sorry for the fuzzy image:
A demo of individual segment control