Talk:Contended I/O

IMHO the "... the ULA halts the processor" is not the best phrase, because there is a HALT instruction in Z80 assembly, which really halt the CPU and the processor is halted while an interrupt arrived. Hmm... o.k. not exactly, because Z80 do NOPs to refresh memory.

This situation the ULA really stops CPU clock signal. pulls the "/WAIT" pin of CPU, and Z80 adds "empty" clock cycles while /WAIT is low. BTW: while Z80 waits, does not refresh the memory, so a long wait cycle can "erase" the DRAM...