Here’s another upcoming little project, tying an ATMega168 to two 8×8 LED displays:
The second chip is an A6279 constant current LED driver with serial in and 16 lines out. This removes the need for 16 LED current limiting resistors and ties up just 3 lines on the MPU. Another 8 lines are used to drive one column of dots. Less than a dozen components (including power regulator) are used in total.
The connectors are: 6-pin FTDI for programming, a combined 2×4-pin SPI/ISP connector, and a 4-pin extension connector with power and I2C signals. The latter could be used to tie multiple 16×8 display units together.
This is just a first impression. Wiring and software are still to-do’s.