BigEd wrote:
So glad you're finding visual6502 useful, and enjoying your CPU-internals journey of exploration!
Hi Ed. There are a couple of "housekeeping" things I would like to contribute to in the expert view, like fixing the scrollbars and looking at locking the headers. There's something funky about that table where you have to scroll all the way to the bottom to scroll left and right, which is particularly annoying when you have plaOutputs and DPControl enabled. Further, it would be nice to lock the headers so that when you scroll down, they remain visible.
Are you folks accepting pull requests these days? This is a great tool and I would love to contribute, even if in a small way.
One other question.. I see some datapath control lines that are prefixed with # and ~. I saw in another thread that this has to do with active low signals and one replaced the other, due to one being more URL friendly.
Now, I am trying to understand how to interpret these. I have been using Hanson's block diagram to follow along, but I see very few scattered active low(or inversion) signals on here. Take DAA for instance. It shows up as #DAA and ~DAA in DPControl, but there's no indication of active low in Hanson's drawing. Should DAA be marked as active low in Hanson's drawing, and it only is in Visual6502 from future discovery? If I see #DAA,~DAA in the DPControl column, should I assume both that the signal is low, but it is considered active, as in DECIMAL ENABLE is ON? If this is all true, then would it be appropriate, for purposes of following data transfer, to ignore active high or low, but that the signal is active, if it is present in DPControl? I hope that makes sense.