exxos's Atari, Amiga & retro forum

rpineau wrote: 13 Nov 2018 23:51 You have ROM_OE on pin 29 :)

cool! :lol: Well was done some months ago, so don't remember :) But may have to move it to another pin depending on routing anyway.

Actually had the wrong SRAM package...

So changed it.. started routing.. but likely wont be doing much more tonight..

Looking good so far

Bit more routing done.. 2 hours to do almost nothing...

Top tip for routing RAM, you can pin swap data bits and some address bits depending on the type of ram used. Probably best just to stick to the data bits though to be on the safe side.

Had a thought to speed up routing.. Basically route everything on the top layer, then use the change tool to change the track layer afterwards.

This saves me having to constantly go to the menu to change layers, and I also do not have the place the vias, as they are done automatically when changing track layer..

ROM making progress...

Been at it all day..

Slowly getting the address & databus from the SRAM to CPU :stars: :stars:

I am also considering adding on some flash onto this. While there is no software for this currently, I can however wire this up pretty much in parallel to the SRAM, where I only need to route a couple of signals to the PLD for programming. The problem I see with this is the physical size, that it will be in the way of the keyboard support post which is to the right the CPU on the STFM.

Another issue that will occur is the ROM chip is now right above the MMU. This will likely mean it will be in the way of my plug-in 4MB RAM kit. We cannot really add things to this board without some consequences somewhere along the line.

Really this is being developed as a prototype for the STF remake. Will of course work in a STFM, physically fitting probably not so much. While I was doing this also as a upgrade from the V2.2 booster, it is also going to be a lot larger because of the SRAM. If I did a version without the SRAM, then it would be a better solution in terms of a V2.2 booster upgrade. But of course doing 2 designs is twice the work.

I will try and avoid the keyboard post hole and get the flash rooted on this board so they can be used in the STFM more easily. But of course, writing software for this someone else will likely have to do this.. But of course worse cases the flash chips just do not get fitted onto this board. But at least the option is there if anyone wanted to take on that project.

Which Flash chips are you thinking of fitting?

I've previously done a fair bit of work with AMD (now Spansion) devices, so I might be able to help a bit with that if you do fit them. :roll:

Just picked up another 1040STF (SM124 isn't working by the look of things) with 2x red LEDs - original (long button) floppy seems to work OK but has TOS 1.0 so that will probably need an upgrade at some point (as well as a PSU recap).
Will check the motherboard revision when I crack the case open but I suspect it will be the same as my first STF (which I bought in April 1987 IIRC with an SM125).