Saturday, 1 July 2017
Z80 M1 signals
During testing of the DivMMC future, one of the aims was that it should work with as many ZX Spectrums as possible. In many cases, the clock line was the most problematic, but we managed to resolve that one (more on that in another blog post).
Given this signal is important for the operation of the external devices, if it's simply not present, then the external devices are not going to work, so you need a new Z80. In all cases where this has been seen, replacing the Z80 has always resulted in a working system.