I have an old MK-328 that I bought several years ago. I think I flashed it back then, as when it powers on, it says "GM328" and the "Show Data" menu reports firmware "1.14k".
Attached is a picture of the front of the case (from the net, but mine is exactly the same). Also, a picture of the PCB (again from the net).
It has a real 328P with an 8 MHz crystal. In the upper left corner are several unpopulated pads. Near the center are missing C9, U2, D2 & L1.
Can anyone tell me what the missing components are for? I assume that some may be for zener testing. Is there a full schematic, showing the missing components? Is it worth the trouble adding a rotary encoder and other missing features?
If I hold down the power button, I get a menu with several choices. Short presses cycle through them, and a long press selects one.