ICD MIO Replica board build completed

[130xeguy]

Well, here's another MIO replica board working out in the wild. Had a few issues along the way getting it working as there are some mistakes on the BOM and some changes to the schematic. But here it is, working proof of concept that you can use a real SCSI HDD with an Atari 8-bit computer. 

 

I'd like to thank member Kenames for all the help on this build. He sold me the bare board and offered as much help as he could in troubleshooting it. Thanks Ken, this project couldn't have happened without you. 

[heroman]

Impressive!

[Ray Gillman]

Wow yes. Can you tell us more about the limits? How much disk space can this afford you and what other benefits?  I owned an MIO once upon a time and still have a 10MB 5.25 inch by like 2 inch tall HD out in the shed somewhere like a paperweight. I would wager a 1% chance it could even spin up after all these years. 98% chance of massive stiction and 1% chance of other issue so I leave it where it is

[130xeguy]

From what I understand, using the latest firmware, each partition is allowed a maximum of 16MB and the RAMDISK is just 1MB

[BillC]

7 hours ago, 130xeguy said:

From what I understand, using the latest firmware, each partition is allowed a maximum of 16MB and the RAMDISK is just 1MB

I believe the later releases of SpartaDOS X are supposed to support 32MB PARTITIONS using 512 byte sectors.

[TGB1718]

This is nice, but I think the one problem is getting hard drives these days, I looked for months for a 50 pin

SCSI drive and apart from some at really stupid prices, there really aren't many around, I did manage to get

a 9GB 68 pin SCSI drive and use a 68pin to 50 pin adaptor (for my ST) and that works fine.

But again I've looked recently and there's not many about.

[+MrFish]

1 hour ago, TGB1718 said:

68pin to 50 pin

You can adapt 80-pin SCA to 68-pin/50-pin too. Should be more-readily available.

 

 

[Jfcatari]

Do you have plans to publish the board and gerbers on Github?

 

[+scorpio_ny]

8 hours ago, TGB1718 said:

This is nice, but I think the one problem is getting hard drives these days, I looked for months for a 50 pin

SCSI drive and apart from some at really stupid prices, there really aren't many around, I did manage to get

a 9GB 68 pin SCSI drive and use a 68pin to 50 pin adaptor (for my ST) and that works fine.

But again I've looked recently and there's not many about.

Hi @TGB1718,

 

This more focused on the classic Mac series that used SCSI hard drives, but they say it should work on other platforms: BluesSCSi

 

Edited November 21, 2023 by scorpio_ny

[130xeguy]

On 11/21/2023 at 9:27 AM, Jfcatari said:

Do you have plans to publish the board and gerbers on Github?

 

It's not my design, so no. I don't have the permissions to do so. Like I said in the original post about this project, it's a build up of a board that was an improvement over the original done by a couple of users here many years ago. They used to offer it to the public, but no longer do so since the development of things like the internal ide and side 2 & 3.

[+MrFish]

8 hours ago, 130xeguy said:

...done by a couple of users here many years ago.

Yeah... you don't see Arabic text on Atari motherboards very often.

 

[+Larry]

On 11/22/2023 at 5:10 PM, 130xeguy said:

It's not my design, so no. I don't have the permissions to do so. Like I said in the original post about this project, it's a build up of a board that was an improvement over the original done by a couple of users here many years ago. They used to offer it to the public, but no longer do so since the development of things like the internal ide and side 2 & 3.

@130xeguy Nice project!  Did you have any issues getting the IC's for the build?  One other thing -- the latest MIO OS does work with SCSI-IDE adapters such as ACARD 7720.  These were being reproduced in China when I last checked, and available at very good prices.  I believe that I even found them on Ali Express.  I also have an Azetc Monster SCSI-IDE adapter and it is even better, since a CF card plugs right into the adapter.  Don't think those are available anymore. 

[kenames99]

I still have a number of these boards available. I just counted 20 but want to keep a few for myself.

 

the biggest problem 130xeguy had was with the frequency the PLL was running and it was too fast. he found a PLL calculator for it online somewhere and had it calculate values for the components and that worked for him. other values worked for me. I have no idea what the difference was caused by. I am happy that his MIO now works.

 

Ken

 

[+Larry]

@kenames99 Have you built one yourself? Maybe years ago?

[MEtalGuy66]

Hats off to you, buddy.. I did about 36 of those, and they suck ass.. over 1400 solder joints.

Warerat also worked his ass off on that project, and deserves all the technical credit. 

 

Be sure and run the MIO diagnostic cart on it for about 24 hours and make sure you don't have any bits flipping anywhere before you trust that thing with alot of work/data storage..  Its a really temperamental design and the Atari's shitty unbuffered PHI2 timing really affects it big-time. In fact, any time you change the load on the atari's data bus (even plugging in or removing a cartridge) you need to reevaluate that thing for stability.  That's just the nature of the beast, i'm afraid..  Same goes for switching from one atari to another.  

 

If you are looking for SCSI devices that tolerate the MIO's half-assed archaic SCSI implementation, Acard SCSI-IDE adaptors and IOMEGA JAZ drives are two devices that seem to work really well. 

 

At any rate, I'm glad to see you got another one working. I gave all those boards to Ken Ames because I'm not gonna build any more. Got better things to do with my life.. 

 

 

[Peri Noid]

5 minutes ago, MEtalGuy66 said:

Its a really temperamental design and the Atari's shitty unbuffered PHI2 timing really affects it big-time.

It sounds like it could be fixed by disconnecting the O2 signal from the PBI connector (I guess, that's how one connects it to a computer) and applying a Phi2Fixer by @lotharek and @Piotr D. Kaczorowski connected to this connection directly with a wire.

[MEtalGuy66]

15 hours ago, kenames99 said:

I have no idea what the difference was caused by. I am happy that his MIO now works.

 

 

The early production ICD MIOs had a variable cap in position CV1.  All of the later ones, both ICD, and mine were built with two 68pf caps in parallel, if I remember correctly. 

 

Edited November 25, 2023 by MEtalGuy66

[MEtalGuy66]

4 minutes ago, Peri Noid said:

It sounds like it could be fixed by disconnecting the O2 signal from the PBI connector (I guess, that's how one connects it to a computer) and applying a Phi2Fixer by @lotharek and @Piotr D. Kaczorowski connected to this connection directly with a wire.

Its nowhere near that simple, unfortunately. The "PHI2FIXER" has been around a long time. It's not a universal fix for anything. It does help some devices behave better. It does not fix the system wide bus-timing issues related to changing capacitance and skew between PHI2 and data bus valid timing.. 

 

[MEtalGuy66]

On 11/23/2023 at 12:54 AM, MrFish said:

Yeah... you don't see Arabic text on Atari motherboards very often.

 

بِسْمِ ٱللّٰهِ ٱلرَّحْمٰنِ ٱلرَّحِيمِ‎

In the name of Allah, the most gracious, the most merciful. 

 

That's the only reason the board works, if you ask me.. 

[_The Doctor__]

5 minutes ago, MEtalGuy66 said:

بِسْمِ ٱللّٰهِ ٱلرَّحْمٰنِ ٱلرَّحِيمِ‎

In the name of Allah, the most gracious, the most merciful. 

 

That's the only reason the board works, if you ask me.. 

It's the only reason anything works :)

[Marius]

This is really cool. I must say, with all the hyper modern solutions, even this hardware feels like nostalgia/retro. I have a blackbox (somehow comparable with the MIO) and I keep thinking that I should revive using the Blackbox again. It was always a very pleasant device and although it would also mean a goodbye to the amazing APT partition system, it would bring so much good memories back.

 

So it is really awesome to see the MIO reproduced this way. I hope there will be more projects like this. And perhaps even a revival of the blackbox...

 

 

[Marius]

2 hours ago, MEtalGuy66 said:

Hats off to you, buddy.. I did about 36 of those, and they suck ass.. over 1400 solder joints.

Warerat also worked his ass off on that project, and deserves all the technical credit. 

 

Be sure and run the MIO diagnostic cart on it for about 24 hours and make sure you don't have any bits flipping anywhere before you trust that thing with alot of work/data storage..  Its a really temperamental design and the Atari's shitty unbuffered PHI2 timing really affects it big-time. In fact, any time you change the load on the atari's data bus (even plugging in or removing a cartridge) you need to reevaluate that thing for stability.  That's just the nature of the beast, i'm afraid..  Same goes for switching from one atari to another.  

 

If you are looking for SCSI devices that tolerate the MIO's half-assed archaic SCSI implementation, Acard SCSI-IDE adaptors and IOMEGA JAZ drives are two devices that seem to work really well. 

 

At any rate, I'm glad to see you got another one working. I gave all those boards to Ken Ames because I'm not gonna build any more. Got better things to do with my life.. 

 

 

This what you write... does this also apply to CSS's The Black Box!? 

I recognize some of the problems you describe I had with a quarter meg 800XL. As long as I used it with Sio only devices, the 256KB was really stable. But connecting the Black Box to this 800XL made it very 'flaky' ... (you could ask @Fox-1 / mnx about his experiences back in the day haha. I am rather sure he has the same memories

[kenames99]

9 hours ago, Larry said:

@kenames99 Have you built one yourself? Maybe years ago?

I have built one. that was why I could not understand why 130xeguy had trouble. I was sure to update BOM because I also had some trouble with mine.

big time kudos go to warerat and metalguy66 for the large amount of time and effort they put into this project!

 

Ken

 

Edited November 25, 2023 by kenames99
add more

[MEtalGuy66]

20 minutes ago, Marius said:

This what you write... does this also apply to CSS's The Black Box!? 

I recognize some of the problems you describe I had with a quarter meg 800XL. As long as I used it with Sio only devices, the 256KB was really stable. But connecting the Black Box to this 800XL made it very 'flaky' ... (you could ask @Fox-1 / mnx about his experiences back in the day haha. I am rather sure he has the same memories

Yes

 

[+bf2k+]

7 hours ago, kenames99 said:

big time kudos go to warerat and metalguy66 for the large amount of time and effort they put into this project!

 

Ditto!!!