You might ask yourself: _is there a font in the ROM?_ Of course there is a font in the ROM.
And now with brightness control! Eight scans of binary-coded, with PWM on the `!EN` channel. Pixel clock is 24 MHz and there are 384 pixels in the shift registers (although 1/3 of the LEDs are not populated).
The wirewrapped ribbon cables are very fragile, although stable enough for testing on the bench.