The big issue is that the HC05 doesn't seem to be available with the necessary 368 bytes of RAM.
One could substitute the 9S08 (HC08 successor) because the HC08 was backward compatible with the HC05, thus simplifying the software port.
But the 9S08 has a very different pinout from the HC05 and that's where "scrambled pins" comes in.
Next easiest would probably be to put the 9S08 on some kind of carrier board , mount the board perpendicularly where teh CUDA was and have 'L' shaped pins soldered to both sides of teh bottom edge of the carrier board so it can be soldered into the original SOIC position.
One would still need to do a little porting with the software as the register names and settings are probably different.
One could substitute the 9S08 (HC08 successor) because the HC08 was backward compatible with the HC05, thus simplifying the software port.
But the 9S08 has a very different pinout from the HC05 and that's where "scrambled pins" comes in.
Next easiest would probably be to put the 9S08 on some kind of carrier board , mount the board perpendicularly where teh CUDA was and have 'L' shaped pins soldered to both sides of teh bottom edge of the carrier board so it can be soldered into the original SOIC position.
One would still need to do a little porting with the software as the register names and settings are probably different.
