ST REMAKE PROGRESS

100% routed :)

Well maybe not exactly as I have a epic amount of tidying up to do yet.  I also need to add in de-coupling caps and the reset switch has gone AWOL.

The "back" IO connectors are basically in the right place. Though I need to measure a real motherboard and make them align with the case properly.  The Cartridge and midi ports are just plonked on just for testing.  As this board is a lot smaller than the original, Then alignment doesn't matter at this point.

I will probably add in a single IO expansion port onto this. Then at least at some point I can route the alt-ram stuff into a card.  Once working, I *might* add that into the next design as a stock feature. Or it may be a custom IO card which may fit under the PSU.   Currently there isn't any room for anything under the PSU, not a expansion card anyway. Though I think a right angle connector which is dedicated to alt-ram would easily fit there.  Then at least its not taking up a main expansion port then.

It has become apparent that the TTL chips, inverters etc, are actually getting in the way of "good" routing.  There isn't much I can do about that. Though I am half wondering about replacing them all with a couple of generic 22V20 GAL's.  Then at least I can make the layout of the chip better to suit my PCB layout.  As it stands, the TTL chips are actually making the design a bit of a mess :(

Similar with the ST-RAM card. Because the Falcon card is 32bit, this means a lot of double routing to convert to 16bit.   There isn't much that I can do about that. Though the bus isolation buffers are also a huge mess of tracks. Again, I may just replace them with a larger PLD. Though I am not sure at this point if its a good idea to move away from dedicated TTL chips or not.  For example, I don't want to force people in the future to use Altera chips (which is what I am using currently).

Ultimately, there will be some more "glue" logic. Which will contain the booster logic. That will be Altera most likely. Though at least it is a optional extra.

So the plan now is to finish off the current design. Lots of messing about with stuff to do now. But it is 100% routed now!

I had a program running to check time to route it, and its about 28 hours! 36,000 left button mouse clicks and mouse moved about 3.5miles!  Considering the work involved I think 28 hours is a huge accomplishment. Of course it will take a lot more time to add in the booster logic, IO expansion headers and other stuff. Though at least this is something now which is almost ready to be prototyped!