On Wed, 9 Aug 1995 13:07:00 +0200, Frode Tenneboe said: > I'm sure. It's 228 on all 128K models (I'm a bit unsure about the original > Sinclair 128K, though). However, there is also a difference between > the +2 and the +2A/+3 being that one is 'in synch' on the first cycle > of a four cycle cycle, while the other is on the second.
Ah but which is which? :-) Do you happen to know what the relationship is between the interrupts and the TV scan? > > This information should be written in the reference section in the speccy > > manual (because it is relevant to the contended memory). > It is? Yes, it is relevant because the memory is only contended while the screen is being drawn. The +3 manual specifically says that this happens for 128 out of every 228 cycles in each scan line, and for 192 out of 311 scan lines. imc
