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STFM motherboard remake project.


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Yeah, I would like to create everything everyone wants. Though even simple things, like re-creating the simms, it took 2 months on and off until that was done. That is a super simple project in itself. So even simple things people want, take a long time, anything more advanced, well, basically forget it, I just don't have the time. People just don't realise the work involved. Most people think something will only take a few hours to do, well maybe so, but more hours to design PCB, build test, debug, takes weeks, months or even years. Multiply that by 100 people wanting 100 Simple things" and thats more like 10 years of my life gone. Work on my boosters has hit a standstill because I am struggling to keep up with stock in my store. So designing anything else, well, not enough hours in the day.

 

There is also the fact that no matter what I develop, likely only 5-10 things of them will ever sell. So I am reluctant to keep spending months of time to develop something which hardly anyone will use. More to the point (again) with all my kits, I have pretty much re-designed the motherboard anyway.. Future kits will become a lot easier to make and for people to fit.

 

Anything is possible if enough people work on things. Just people have to realise, I am not "super man" and can't create the 200+ hour day. So 99 projects won't get done, thats just how things are. I do know what everyone wants, and yes it will be done as addons eventually, and yes they will be included as "Stock" on the new board, but that is likely some years away as there is a lot of work to be done.

I don't know why you even do it Chris, but it is truly appreciated. Every kit I have purchased from you is the best quality.

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A sneak preview of the new "STF".

 

This has some basic mods as talked about in my blog. http://exxosnews.blogspot.co.uk/2017/07/stfm-rebuild-overview-of-basic-changes.html

 

So this is just the "bare bones" of the new "Super ST". Or basically a STF with some IC package changes and a few others minor mods here and there. This way it is easier to debug why it doesn't work :)

 

post-7597-0-67771400-1500711571_thumb.jpg

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I was looking over the picture you have on your blog of the STFM motherboard. Would it help you at all to have a picture of the STF, since you're going to not include an RF modulator anyway, it really shows how much empty space is there? Unless you already have said picture. This really is a 'new STf motherboard' :P

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I was looking over the picture you have on your blog of the STFM motherboard. Would it help you at all to have a picture of the STF, since you're going to not include an RF modulator anyway, it really shows how much empty space is there? Unless you already have said picture. This really is a 'new STf motherboard' :P

 

Thanks, though the board I have been using is the STF version. The image on my site was just one I grabbed to illustrate what was going on :)

 

I had to take a STF to remove some sockets so Rodolphe could make a lib for me anyway. Lots of IC's are "missing" on this board as it was used for spares. May take a image on my next blog post..

 

As there will be no RF, and the Shifter stuff is like the MEGA ST (IE less stuff) then there isn't anything needed other than the RGB drivers. As such, the shifter will be placed where the RF box was. This means the RGB signals are going right to the port, not across multiple other signals on the PCB. This will mean the RGB output will be a lot cleaner. I always see odd patterns in desktop windows. So I hope this will help resolve such noisy patterns.

 

12V isn't actually needed on this board, So a smaller PSU could be used. Though if there is still noise on the RGB lines, I may drive them with 78L05 regulators to help stop the RGB "crosstalk". I've had similar issues with Digital Audio amps I have designed in the past. Its better to drive stuff individually to take the load of a signal supply rail. Though as to if there will be noise, I don't know yet, if there is, I can try regulators on the RGB circuit, though it will mean the PSU will need 12V again.

 

I suppose there could be other options to add some filtering into the 5V line. Its what Atari attempted to do, though driving the RGB lines off 1 filter is a little pointless. Anyway, once a new board is done, I can see what it turns out like, and try some things out to resolve and find the best solution.

 

In anycase, the RF port being removed is going to cut down on a lot of interference around the board and with the shifter and RGB drives being located next to the RGB port, hopefully that in itself will be enough to stamp out all the noise issues.

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This is the motherboard I have been working with.

 

With no RF parts there is a fair bit of room. Also a lot less parts around the shifter. Though half the parts there are the 32mhz gen. So can be replaced with a 32mhz osc like on the MEGA ST to save even more space and parts.

 

Rodolphe also suggested the MAX232, so on rev2 will likely use that. Whole lot less parts saving cost and space.

 

Also as future thoughts. A lot of the TTL logic could be replaced by a single PLD. It could also hold booster logic and many other things...

 

post-7597-0-76444500-1500903567_thumb.jpg

 

 

post-7597-0-16880000-1500903599_thumb.jpg

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Please keep up with the updates - it's great to read how you're figuring it all out. :)

 

As someone who is terrified of upgrading their stock STFM due to the prospect of having to cut up parts of the case or shielding to fit things in (but knows it'll need to happen eventually to keep it running), the possibility of getting a compact motherboard that works just like my old machine but allows the room to hide upgrades internally has a lot of appeal. If it means I don't need a crash course in soldering all the better. ;)

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Please keep up with the updates - it's great to read how you're figuring it all out. :)

 

As someone who is terrified of upgrading their stock STFM due to the prospect of having to cut up parts of the case or shielding to fit things in (but knows it'll need to happen eventually to keep it running), the possibility of getting a compact motherboard that works just like my old machine but allows the room to hide upgrades internally has a lot of appeal. If it means I don't need a crash course in soldering all the better. ;)

 

:) Yes, There is easily room for 3 falcon sized expansion cards on this board so far. I think there will be a lot of room near the front of the case for stuff, but not enough room for expansion connectors. Ultimately it will probably be space for adding in my booster logic or something.

 

I'm 30 hours in and about 160 wires to go. Had to move some stuff about.. now just left with all the fiddly bits to do really..

 

 

post-7597-0-74543800-1501784463_thumb.png

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Nice work! :thumbsup:

 

Just taking the connectors and chips as a guide to the size it already looks like you've shrunk it by a huge amount. :) With the RF Modulator gone you'd now have a neat little hole at the back of the STFM case too. Would that be big enough to fit a connector or wiring for external devices (say a cased HxC)? Guessing though people would use it to mount a toggle switch (ROMs, Drives, etc) which is a nice neat solution.

 

Apologies in advance if anything said is wrong - I'm learning as I go. :)

Edited by TheNightOwl
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Nice work! :thumbsup:

 

Just taking the connectors and chips as a guide to the size it already looks like you've shrunk it by a huge amount. :) With the RF Modulator gone you'd now have a neat little hole at the back of the STFM case too. Would that be big enough to fit a connector or wiring for external devices (say a cased HxC)? Guessing though people would use it to mount a toggle switch (ROMs, Drives, etc) which is a nice neat solution.

 

Apologies in advance if anything said is wrong - I'm learning as I go. :)

 

Yeah the RF box saves a lot of space. Not sure about the "RF hole". Some users in France don't even have the hole. I'm not sure what will go there in that space. Probably some IO port for alt-ram or something would probably be ideal.. Its a bit early to be thinking about that at the moment anyway. Currently I am just trying to clone the STF and get that working stable first.

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Very nice work! Are you planning to release the schematics and/or PCBs under a permissive license?

 

The schematic as it is has already been released. I will do a page on my site about it in due time. I want it to be open source so people can make addons for it and built it into a better machine over time.

 

Currently I am just cloning the STFM to make sure it works, if anyone wants a PCB of this original prototype , then I may get some more PCB's made. Though I don't really plan to produce this current PCB, as I am already planning a version 2.

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Yeah the RF box saves a lot of space. Not sure about the "RF hole". Some users in France don't even have the hole. I'm not sure what will go there in that space. Probably some IO port for alt-ram or something would probably be ideal.. Its a bit early to be thinking about that at the moment anyway. Currently I am just trying to clone the STF and get that working stable first.

Cool, mine is a 1040 STf anyhow, no modulator hole. Any chance for a scan-doubled video output there? Just asking because I'm getting my 130XE overhauled with all the upgrades, and one of the things that will be done is the RF modulator will be removed, and a proper RGB video out will be put there. Since the ST already has an RGB out, a nice VGA out would be cool. I just don't know how feasible that is.

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Cool, mine is a 1040 STf anyhow, no modulator hole. Any chance for a scan-doubled video output there? Just asking because I'm getting my 130XE overhauled with all the upgrades, and one of the things that will be done is the RF modulator will be removed, and a proper RGB video out will be put there. Since the ST already has an RGB out, a nice VGA out would be cool. I just don't know how feasible that is.

 

Scan doubler really needs a new shifter designed to output HDMI. If someone did design it, then sure I will add it. Though I think nobody is likely to ever design one. I have enough projects to keep me going for the next 10 years, so nothing I am able to do myself.

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You know what would be nice? A list of people who are into the scene, but are actually looking for projects to work on and have the ability to do them. Like SainT with his thoughts about tackling an ST portable. But of course there are those that are VHDL skilled, or those that are good at making schematics. So would that require a fully new shifter, or could we get some sort of passthrough added to the video lines so an upscaler chip could be slapped in the middle? Granted all the boards I've seen for that are large, and wouldn't sit where the RF modulator used to be.

 

I like how the Indivision does it on my Amiga, you slap a socket over the video chip and it has an output for VGA/HDMI. But from other talks, sounds like that's not quite possible on the ST.

Edited by leech
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Problem is as always, nobody hardly can solder, never mind build anything. The ones that can, are generally to busy or not interested in the stuff I do.

 

There are some people who help out with stuff, like Rodolphe did the motherboard libs for me. Though that is pretty much it in terms of current help. Of course I get some help form various people with various projects, but Basically everything I have to design myself from the ground up. This is why I say "no" to like 90% of projects people want me to do, simply because I just don't have time or funds.

 

As I said many times before, I don't have time to work on my booster projects anymore, nevermind take on anymore projects, and the boosters was the only thing I was really interested in doing. Though I got side-tracked into keeping existing machines up and running and debugging and doing fixes for them, like the DMA, video issues etc. That is all the time I have. I am working on Atari stuff 10+ hours each and every day. I would love to do everything people want, but I just can't do anymore work.

 

I am only developing this new motherboard as I am just tired of tracing bugs which are down to noise and bad layout of the motherboard. Not only that, I am spending so much time trying to get things to physically fit that its just become tiresome. Multiply by 20 motherboard variations and the fact almost nobody can solder, or has the motherboard I design upgrades for, and it just becomes pointless to work on existing machines anymore.

 

If people want to develop addons for this new board, then they will have to do the work for it. Though myself and Rodolphe already tried to get interested in a booster development board, and expansion cards for our boosters over 2 years ago now, and nobody was interested then about developing addons, so it falls back on ourselves to do all the work. Which we don't have time to do.

 

To be honest, once this new board is done, and my booster tech is added, I really don't plan on developing anything else at all after that. I really don't want to spend the rest of my life only doing Atari projects :)

Edited by exxosuk
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To be honest, once this new board is done, and my booster tech is added, I really don't plan on developing anything else at all after that. I really don't want to spend the rest of my life only doing Atari projects :)

 

It would be kind of hard to out do this one anyway. Better to go out on a high note as they always say ;) .

 

- Michael

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I am interested in donating to help, and can donate time to validate. I only know very basic electronics but if there's some way I can contribute some time I'd like to. I don't mind testing boring stuff like serial and MIDI for example.

 

I would recommend avoiding kickstarter for fees reasons.. Every $ helps in a campaign like this.

 

On the STE - does the combined chip share one clock input then? vs. separate clock inputs for GLUE and MMU on STFM? I'll say from a USA perspective, STEs are very hard to come by..

 

From the post, it sounds like the requirements you're proposing are:

 

- Open Source

- Fits in ST(fm) case with ST(fm) ports

- Low cost and already available RAM options preferred

- Uses original ST chips - MMU, GLUE, SHIFTER, DMA, and 68000

- Priority is something that can be built quickly

- Through-hole for hobbyists

 

Can you talk a little bit about the power circuitry? Would it be possible to design for use with a simple 5V (i.e. USB, but maybe high amperage) input to make that something easy to source?

 

Also, this adds complexity, but are you set on using standard TOS ROM chips, or would a more modern EEPROM of some kind (or something software flashable) be possible/ideal? (or too much work).

 

Thanks!

John

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The ports will need testing once the PCB is manufactured. I don't think I have anything anymore which uses any of the ports.

 

PSU, will be using my own designed PSU. I don't trust any other PSU's out there which I have not designed or tested myself personally. Though if people don't want to do that, they can upgrade their old PSU.

 

This is a prototype board which uses PLCC ROM like my boosters do. I am looking into flash, but can't work on everything at once by myself so everything takes time.

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exxosuk,

Don't rush and don't feel bad about taking the time to get this right. Quality needs time. Looking forward to seeing the finished product. I probably won't be a buyer, but it always neat to see a new product for these machines.

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As there is talk about motherboards lately...This isn't to discuss "addons" and what the new motherboard should or should not have, or what motherboard is to be done. This project is to create a clone of the STFM ONLY , which basically has an array of expansion ports to upgrade easily. There will also be some general improvements and modifications, such as moving away from 6 chip ROM to a single 4096 PLCC ROM.

 

This sounds really awesome to me. The only thing I'd really want is an easier way to attach a modern display. I really don't want to stick to small CRTs. :)

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