This new Card takes advantage of the smaller PLCC package size for the CPU and ROM, to enable combining the functionality of these two previous Cards into an attractive PLCC based design.
I like PLCC packages, as they're not only attractive to look at, they're also satisfying to insert into a PLCC socket! The PLCC sockets are also available in the Retro friendly Through-Hole (TH) format, which I've used here.
I've also chosen the HD63C09 CPU variant, to provide the fastest manufacturer rated clock speed for a 6809 compliant CPU Card (3MHz), and I've also used fast 15ns SRAM and 70ns FLASH ROM to allow faster over-clocking! As such, my initial testing of the new Card was with a 16MHz oscillator (4MHz CPU speed). Of course, over-clocking is not recommended, so if you want to replicate this (or go even higher), please remember you do risk damage by exceeding manufacturer ratings.
Because of the above, I think this is currently my new favourite MECB CPU Card!
You can view and read more about it here: Minimalist Europe Card Bus (MECB) - 6309 PLCC packaged CPU Card