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Thanks for the blog, I read every post. I'm curious about the circuitry that drives the difference between "minimum" and "maximum" modes from the processor - a
by andrewf 3y ago
Thanks for the blog, I read every post.
I'm curious about the circuitry that drives the difference between "minimum" and "maximum" modes from the processor - another Intel pin-saving strategy. Is there basically an 8288 sitting in a corner of the 8086 die, or are things more complicated than that?
- kens 3y agoThere's not really much to the minimum and maximum modes. You can think of it as multiplexers on the relevant pins, selecting the signal for the appropriate mode. (Of course, the logic isn't quite that clean but that's the basic idea.)
- andrewf 3y agoThanks. I guess what I'm wondering is whether the maximum-mode signals (S0, S1, etc) are somehow more fundamental to the 8086's operation, with the minimum-mode signals (WR, INTA, ALE etc) being derived from them solely for the benefit of people without an 8288? Put another way, if you could, recursively, delete all the gates in the 8086 which only exist to drive minimum-mode pins, would any remnant of the minimum-mode signals remain for other internal uses?
- kens 3y agoI haven't looked at the signals from that perspective, but I'd say that both sets of signals are derived from various internal signals that are more fundamental.