I worked a bit on robust configurable serial I/O (UART, GPIO with interrupt, mixed, full/half duplex), and there will be some more work to do until I'm satisfied with the result. Currently I'm testing the W1209 with the new code.
Many boards have a 7S-LED display and I doubt that many will have the same GPIO configuration. On Taobao and on AliExpress there are dozens, and I ordered a bunch in the lower single digit $ range to play with.
My goal is to have a generic I/O module for the console, with little dependencies to board specific initialization and driver code. Serial I/O should be the first thing that works, and the last thing you should be required to change the code for supporting a new board.