New HDX crossplatform server, and HDX hardware design discussion

[Willsy]

Yes I think I would be interested in writing a DSR for that. What are you thinking hardware wise? Would it would have any RAM? There's a lot I need to find out about writing DSRs - I've never even looked at it!

[ckoba]

The HDX is a great idea and Fred is a great guy. I haven't heard from him in a long time. He's kind of dropped off the radar a bit. I think with the HDX he just took it as far as he was able to within the normal constraints of a hobbyist project. And he never sold them; he just made everything available on his site -there's no warranties or guarantees. Don't be too hard on the guy. If you met him you'd like him. And we need talented guys like Fred around!

 

I've never met the guy, nor do I think I ever will. All I know of him is from his work on the HDX. He could be the nicest guy on the planet, but I still wouldn't hire him as either a software or a hardware engineer.

 

(Is he still around?)

 

Yes I think I would be interested in writing a DSR for that. What are you thinking hardware wise? Would it would have any RAM? There's a lot I need to find out about writing DSRs - I've never even looked at it!

 

The only real question at this point is what UART you want to use/are familiar with programming.

 

The 16550 is available. Bog-standard PC UART, shouldn't be difficult to interface to the card -- I'd just need to unravel the GAL equations and see if it's doing anything weird with clocks or suchlike.

 

I like the 6551, which is also still available as the WDC65C51N. It has an interesting hardware bug affecting the transmit-buffer-empty bit in the status register, though, which affects polled TX. From the errata:

 

The W65C51N has an operation issue concerning TDRE. This bit is not being reset after loading the

Transmitter Data Register. Polling the TDRE bit of the status register will never show the TDR as Empty.

Due to this issue, the W65C51N is not suggested as a direct replacement for older 6551 devices if the

firmware uses this bit. It is recommended to using IRQ handling or software timeout for transmission as a

workaround for this issue.

 

... which I consider to be a show-stopper for this application, because of the TI's insistence that *everything* be polled I/O.

 

Beyond that, you want it, you get it. You'd lose a page at the top of the memory space for the UART; the rest of the memory space can be sliced up into EPROM and RAM as you need. I reckon we'd use anything up to a 27128 for the EPROM (because they're plentiful), and a 6264 or 62256 for the RAM (ditto for the latter); how that's divvied up into the 4k space after the UART's page is accounted for is up to you. One request: please keep the boundary between EPROM and RAM on a page boundary

 

(edit: "up to 27128" and "62256" not because we'd need the extra space, but because the pinout is compatible with the 2732/2764/6264. Just need to ground or pullup the various unused pins on the low-size chips so that the larger-size chips' address lines aren't left floating)

Edited February 20, 2016 by ckoba

[+Lee Stewart]

On 2/20/2016 at 4:37 AM, Willsy said:

The HDX is a great idea and Fred is a great guy. I haven't heard from him in a long time. He's kind of dropped off the radar a bit. I think with the HDX he just took it as far as he was able to within the normal constraints of a hobbyist project. And he never sold them; he just made everything available on his site -there's no warranties or guarantees. Don't be too hard on the guy. If you met him you'd like him. And we need talented guys like Fred around!

 

Fred was last on this forum on December 15, so he has not seen any of this thread. In fact, he has only one post here since he first logged into this forum on July 5, 2014. Here is his one and only post (HDX -- Users / Status Update, post #13😞

 

On 7/5/2014 at 9:15 AM, F.G. Kaal said:

Hi all,

 

I was just browsing through Atari-age and found this HDX topic and read about problems, requests and e-mails send to me about the HDX device.

I have never received any e-mails from this forum but I can be reached via a PM.

 

Fred

 

FYI, Fred's website has changed to http://hexbus.com/ti99geek/

 

...lee

Edited April 24, 2023 by Lee Stewart
website change

[+InsaneMultitasker]

The author was invited to participate, or at least comment, in the first post on the subject -- and either doesn't live here anymore (contrary to Arcadeshopper's belief), doesn't care to see his creation ripped to shreds, or doesn't care period. Willsy says that the author was aware from the very beginning of serious issues with the HDX, but only fixed some of them. I conclude that the HDX is, at this time, unsupported by the author.

 

(I'm also amused that no credit was given by the HDX author to InsaneMultitasker for the BASIC test case suite. That's rather rude, but in keeping with the mental image I've formed of the author over the past few weeks)

 

Therefore: I cannot in good conscience recommend the HDX to any TI user, because it is not reliable and can not be made reliable as long as it uses the TI serial hardware. I'm sorry if this dissuades people from purchasing HDX boards/installation from your store, Arcadeshopper, but the HDX is junk. If it were a Commodore device, it would have been a Jim Drew product.

 

This thread has become distasteful over the past few days.

 

Fred has always been open to feedback concerning his software and hardware, within the constraints of real life. As Lee pointed out, Fred has not visited this forum in some time; he cannot participate in something for which he has no knowledge.

 

Regarding the test case suite, I did not write the programs. I provided test cases to Fred, from which he wrote programs to test the various IO. As far as I can tell, the IDE DSR problems were corrected. Whether or not all of the IO-related fixes made it into the current HDX DSR/server, perhaps not. Only Fred can tell us what he did/didn't do. I apologize if I inferred something different.

 

 

Perhaps a reminder is in order for all of us reading this thread:

 

Fred has contributed a lot to the community and has done so freely. Like him, most if not all of us here write programs, fix hardware, or create hardware as a hobby. We do it for fun, we do it to learn, and we share ideas.

 

To continue to berate Fred for his efforts, even with the problems you have encountered, is discouraging to me (and perhaps others). While I am excited to see what new device comes out of the discussion, and am willing to participate, I am not willing to be a party to the continued thrashing.

 

For those who use and appreciate the HDX as it is today, let them enjoy what works for them. For others who want something with more reliability and robustness, they can wait and/or participate in something new.

[+arcadeshopper]

 

Fred has contributed a lot to the community and has done so freely. Like him, most if not all of us here write programs, fix hardware, or create hardware as a hobby. We do it for fun, we do it to learn, and we share ideas.

 

To continue to berate Fred for his efforts, even with the problems you have encountered, is discouraging to me (and perhaps others). While I am excited to see what new device comes out of the discussion, and am willing to participate, I am not willing to be a party to the continued thrashing.

 

For those who use and appreciate the HDX as it is today, let them enjoy what works for them. For others who want something with more reliability and robustness, they can wait and/or participate in something new.

 

Right there with you. There's no reason to be so negative. Nothing good will come of it. The HDX is provided gratis to the community. If someone can make a better system, go for it. But lay off the continued thrashing. It's unnecessary and unwelcome. The TI community is too small and people will just check out of the conversation if it's not productive.

 

Greg

[ckoba]

Okay, I'll dial it back several notches. Thanks for the feedback thus far.

[F.G. Kaal]

Hi fans, here a message from me te let you all know I'm still arround.

 

Just a little history:

I started the HDX project somewhere arround 1995 (called Ti2Pc then) when I was mostly working with my Ti99 and Geneve and had a PC with an Intel 386 precessor and MSdos 6.1.

 

The very first version of the HDX server was an MS-DOS program with which a could load and save (level 3) programs. I have made my own serial interface-card and used an Intel 8251 UART because that thing was just laying arround. The seconde version had a parallel interface with a 8255 PIO on both the TI and PC side. A few PeeCee's later I had to change the HDX interface again because my new computer didn't had an ISA bus anymore. This time I used an 16C550 UART at the TI-side and I could do 15K200 baud.

 

I demonstrated this concept on many occasions, the first time was at the 12th Annual European TI99 user group treffen at the Ibis hotel in Utrecht. Many times at the dutch TI user group meeting the members spoke about saving TI-files on a PC at which I repplied "what about the HDX software I always demonstrate?". But building an expansion card for the PEB is for many users just a bridge to far. This was why I added the HDX code to the original Texas Instruments RS232 card: most users allready have this card in their PEB and now they only thing to do is to replace the (E)PROM by a RAM and off you go. But also this is to difficult for many users.

 

Why use a RAM with battery backup instead of an EPROM?

This makes replacing the DSR much more easier. I don't have to start an EPROM burning factory to supply every user with a new version. The little circuit for the battery backup is the same as used in the mini-memory module. I myself have to reload the DSR just once or twice over 5 years, the same whith the IDE DSR.

 

Why no handshake:

I don't need it. Messages are short enough to fit in the receive buffers. If it doesn't fit then there is something wrong and the sender must resend the message.

 

Powerup sequence:

The HDX DSR checks for the DSR input. If not here, the PC is not switched, the HDX server is not running or the cable is not connected.

If it is there, an initialisation is send over to the PC which should be answered. The TI waits for an answer but the timeout value is a bit high (>7FFF). This needs some fine tuning (but I doesn't care at the moment). This is what I user can experience as a frozen TI system but if you wait a bit longer the tile screen appears).

 

I have spent a lot of time in debuging and testing the relative file access to get that right and as far as I know it is all functioning properly. Because the HDX DSR/Server, IDE DSR and my emulator Ti994w all share the same methods of access files these problems could be solved in al these programs at the same time. It is a bit disappointing to read that this still seems not to work properly and people just doesn't bother anymore to mention.

 

(Also) for me everything according the TI99 is a hobby (project) and at the moment I am busy on my emulator and the Editor/Assembler file EDIT1 for a new version of the Editor/Assembler II (or III) module. I don't reply much because browsing and replying on all those forums eats up the time I wishes to spend on fun things. I do everything for free and give everything away, liefdewerk ... oud papier (charity, old paper) as they say here in the Netherlands.

It feels nice to read that some people are very happy with the HDX as it is. It is also nice to read that this inspires other people to create another implementation of the HDX. Just one request: If this new implementation is NOT compatible with HDX then don't name it HDX but give it another name.

 

Well ... to make a long story short, for your entertainment ...

 

the HDX DSR source can be dowloaded here: http://www.ti99-geek.nl/Projects/ti99hdx/ti99hdx_ti_rs232.html

the HDX server source can be downloaded here: http://www.ti99-geek.nl/Projects/ti99hdx/ti99hdx_server.html

 

(I'm proud of the HDX DSR and I am aware that the HDX server code does have uggly things and it can all be done better, it all grew like this in the past years)

 

 

and mr. ckoba ... I am so happy I am not working for you.

 

but enjoy anyway and create something beautiful for the TI community.

 

 

Fred

[Willsy]

Hi Fred nice to "see" you again!

 

I'll be able to provide more info on HDX issues in a couple of weeks as I will finally be setting my real iron up again for the first time in around 5 years :-)

[+arcadeshopper]

Ok I powered up the Geneve today (for other reasons too!) and HDX worked flawlessly. Went in GPL with rompage using DM2k and copied files to the Geneve disk drives without issue.

 

Greg