The M68EC020 processor has been used as the base processor in some Amiga models most notably the A1200, and the primary difference between the MC68EC020 and the MC68020 is that it has a 24bit address bus.
Here I happen to have a board with an MC68EC020RC20 on the top of the socked, and I replace it with an MC68020RC25 the board doesn't start.
Everything is tested and known of being working, e.g. the MC68020RC25 works for another board.
The starting address is below the 24bit address space, it's located at 0x0080.0000, as well as the stack is located at 0x0000.1000
czietz wrote:Considering that even Vcc and GND are different if you're unlucky you have now fried the 68020.
Not fried, the chip is still alive and passes all the diagnostics. I put a current limiter on the CPU board. Anyway, what a stupid design of the package by Motorola, and the documentation of the Socket was not telling about the different pinout
Lesson learned: you must always check the datasheet!