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jedimatt42

32k expansion for the side port - released

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I hadn't thought about that... by kit form, you mean 'board plus components, assemble yourself?'

 

Yes, like the FlashROM 99 is offered. Unless of course, it makes no difference in price. Then I'm happy to let you do all the work. :lol:

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So I will be able to hook up a external disk drive after the 32K?

You will not be able to hook up edge card based sidecar devices after the 32k, unless you build an adapter from IDC style header connector to edge card.

 

You will be able to put the 32k at the end of any traditional TI sidecar devices.

 

You will be able to design expansions that connect as daughterboards to the 32k board. So a storage solution could be added if one is designed.

 

[email protected]

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getting mounting holes just right is a perennial problem on board designs. . .it is one of the hardest parts of the layout!

 

They're called, at least when I still worked at a PCB shop, tooling holes, and are also used for registration for electrical test to align the finished board on a fixture. When you get more complex in your designs with tighter pitch SMT and multiple layers, you really need them. Often they're left unplated which allows for tighter tolerances since plating and solder makes the finished size a little less predictable.

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You will not be able to hook up edge card based sidecar devices after the 32k, unless you build an adapter from IDC style header connector to edge card.

 

You will be able to put the 32k at the end of any traditional TI sidecar devices.

 

You will be able to design expansions that connect as daughterboards to the 32k board. So a storage solution could be added if one is designed.

 

[email protected]

 

 

Maybe when you get the boards into production and I talk to you about cost to add one for me.

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Yeah, I know how I would design the edge card adapter to the right, I just don't see a market.

 

I don't understand what use case requires it. I would be happy to have that discussion.

 

My primary design focus has been around keeping cost down for the main use case. cartridge users.

 

[email protected]

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My primary design focus has been around keeping cost down for the main use case. cartridge users.

 

This project is exciting on so many different levels to me. I like your approach for keeping it simple and the cost low as possible.

 

Why?

 

1) I believe there is a larger demographic than we know that would love to get back into the TI, but does not want to drop a fortune.

2) There are gamer's that collect multiple platforms. This device will give them a quick and simple way to access 95% of all games inexpensively.

 

This 32K device, paired with the FlashROM 99, will let nearly anyone access "GOBS" of programs on R.I. Just download and put on the SD card.

 

I also believe the JediMatt 32K paired with the FR99 on a stand alone console may act as a 'gateway drug' to bring more people into the hobby further. Once they cut their teeth on the FlashROM, some of them might want to continue upgrading... after all, "In for a penny in for a pound".

 

In the end, I think this will bring more people into the TI community here on A.A. and who knows where that will lead?

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This project is exciting on so many different levels to me.

.....

 

1) I believe there is a larger demographic than we know that would love to get back into the TI, but does not want to drop a fortune.

.....

I also believe the JediMatt 32K paired with the FR99 on a stand alone console may act as a 'gateway drug' to bring more people into the hobby further. Once they cut their teeth on the FlashROM, some of them might want to continue upgrading... after all, "In for a penny in for a pound".

 

In the end, I think this will bring more people into the TI community here on A.A. and who knows where that will lead?

 

People like me! After nearly 30 years since I gave away my first TI-99/4a, I found another at a yard sale. I've since ordered a FlashROM99 and an F18a vga card.

So, to keep on topic, I await with unbridled impatience ;-) for this 32k sidecart to be a reality! But, I guess, after 30 years a few more weeks or months is bearable.

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I received the components for the sample last night... This morning I assembled a board.

 

I tried the 74HC245 bus transciever, but that failed memory tests. It did however play parsec better than my earlier breadboard prototype.. although parsec would still crash before the 'bzzz-bzzz-bzzzst' baddies. I was bummed... Any of a million things could be wrong. But, since it sort-of worked, I focused on the data bus. I swapped out the HC chip for a nice old fashioned LS, and gave it a test...

 

Rock solid!

 

Then I decided to compare datasheets and build an understanding as to why that might be ( you might think that my behavior is backwards... :) it is. ) The HC chip is lower power, but also that comes with lower output power. Given that it needs to signal back into the console through edge card connectors, I'll take that as explanation enough.

 

Here are some photos of the assembled unit, connected to a TI, some different angles of it disconnected.

 

https://goo.gl/photos/a9c1BtSKucaPukhQ6

 

To solve the problem of extending the edge card connector far enough to the left, so that a plastic case could one day be there, I found a supply of single-pin machined sockets ( a 1 pin socket ) and just needed 44 per board --- so that was $1.20 a board, instead of edge card connectors with long leads... It is only 44 more solder points per board... And with 44 of them, it is strong.

 

The board is using 63ma. It just doesn't work off the side-port's +5v with the 50ma limit... I'll leave the selector/jumper, but it will require modding the TI to allow more current out the sideport. It looks like most of that current is the 62256 memory chip. Or maybe a source of much lower power 32k sram chips...

 

Anyway, enjoy the pictures.

 

[email protected]

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I received the components for the sample last night... This morning I assembled a board.

 

I tried the 74HC245 bus transciever, but that failed memory tests. It did however play parsec better than my earlier breadboard prototype.. although parsec would still crash before the 'bzzz-bzzz-bzzzst' baddies. I was bummed... Any of a million things could be wrong. But, since it sort-of worked, I focused on the data bus. I swapped out the HC chip for a nice old fashioned LS, and gave it a test...

 

Rock solid!

 

Then I decided to compare datasheets and build an understanding as to why that might be ( you might think that my behavior is backwards... :) it is. ) The HC chip is lower power, but also that comes with lower output power. Given that it needs to signal back into the console through edge card connectors, I'll take that as explanation enough.

 

Here are some photos of the assembled unit, connected to a TI, some different angles of it disconnected.

 

https://goo.gl/photos/a9c1BtSKucaPukhQ6

 

To solve the problem of extending the edge card connector far enough to the left, so that a plastic case could one day be there, I found a supply of single-pin machined sockets ( a 1 pin socket ) and just needed 44 per board --- so that was $1.20 a board, instead of edge card connectors with long leads... It is only 44 more solder points per board... And with 44 of them, it is strong.

 

The board is using 63ma. It just doesn't work off the side-port's +5v with the 50ma limit... I'll leave the selector/jumper, but it will require modding the TI to allow more current out the sideport. It looks like most of that current is the 62256 memory chip. Or maybe a source of much lower power 32k sram chips...

 

Anyway, enjoy the pictures.

 

[email protected]

 

Awesome. I can't see the pictures though. Perhaps you're still uploading them.

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Excellent news! :) I like the trick with the pogo pins. . .

 

It looks like the pictures are set to private as opposed to public, as I can't see them either (and I have no Google account, so I can't log in to test either).

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Awesome. I can't see the pictures though. Perhaps you're still uploading them.

 

They seem to come and go. Try reloading the page (F5) a few times.

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People like me! After nearly 30 years since I gave away my first TI-99/4a, I found another at a yard sale. I've since ordered a FlashROM99 and an F18a vga card.

So, to keep on topic, I await with unbridled impatience ;-) for this 32k sidecart to be a reality! But, I guess, after 30 years a few more weeks or months is bearable.

 

Welcome back to the TI universe! You'll find this place addicting. There are so many TI gurus, hardware hacker and software guys hanging out here it'll make your head spin. The stuff they come up with will continually blow your mind.

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As promised, here are the pics in the album.. ( which is shared, open to anyone with the link: https://goo.gl/photos/a9c1BtSKucaPukhQ6) The album has higher res, if you want to zoom in on any details...

 

post-42954-0-17511800-1474756051_thumb.jpg

 

And, if it brings more players to the high-score thread, and/or more cross-compiling-cart-game-builders, that will be awesome for everyone.

 

[email protected]

 

 

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Still can't see the Google pix for some reason, probably because I am not logged in to their system. . .

 

I got the data I needed from the low-res pix though, so all is good. :) :) :)

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jedimatt42, on 24 Sept 2016 - 9:25 PM, said:

 

I tried the 74HC245 bus transciever, but that failed memory tests.

 

Try a 74HCT245 (HC*T*). The logic levels for the HC range aren't directly compatible with the 74LS/TTL chips used everywhere else, but the HCT range is.

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Try a 74HCT245 (HC*T*). The logic levels for the HC range aren't directly compatible with the 74LS/TTL chips used everywhere else, but the HCT range is.

 

Thanks! I must have mis-read something in the past... I'll give those a shot.

 

[email protected]

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Yeah, I know how I would design the edge card adapter to the right, I just don't see a market.

 

I don't understand what use case requires it. I would be happy to have that discussion.

 

My primary design focus has been around keeping cost down for the main use case. cartridge users.

 

[email protected]

I have a stand alone disk drive that I would like to connect to it. My stnd alone 32K dies some time ago. I don't see it being a massive run, but if this is something you would make me one or two I would love to get them from you.

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I've taken Karsul's feedback on the holes.. :) I hadn't actually performed any physical analysis prior to this... and revised the board layout..

 

The holes in the corner are intended to aid mounting in something... So I have extended the edges of the board, increased the size of those holes, and now they are placed where they should clear all of the edge connectors, power jacks, chip sockets, etc...

 

I'll have the demo units I'm building this weekend at PRGE, but I cannot promise having the final boards ready by then. Turn around time is 2-4 week to get the boards printed. If I get them in 3 weeks, I'll have time to build some distribution units.

 

Here is a preview of the ammended layout:

 

post-42954-0-36257700-1474822365_thumb.png

 

I'll be staring at it for a while, and then submit the order today.

 

[email protected]

Edited by jedimatt42
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I have a stand alone disk drive that I would like to connect to it. My stnd alone 32K dies some time ago. I don't see it being a massive run, but if this is something you would make me one or two I would love to get them from you.

 

What brand of disk controller was that?

 

[email protected]

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There are two stand alone disk controllers: the sidecar PHP 1800 from TI and the TX99 from Percom Data. Both of them are single-density, and I believe only the Percom will do double sided. . .though to tell the truth, I've never tried to use a double sided drive with my TI sidecar.

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Ah, the percom didn't have a standard expansion to the right. Some googling makes it sound like it only has a second port for another percom disk drive.

 

Something like this:

 

post-42954-0-63953500-1474949771_thumb.png

 

With some of these (cut to fit):

 

post-42954-0-20763400-1474950511_thumb.png

 

should do the job. Not 100% sure about the reach of the right angle female header...

 

[email protected]

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