gregallenwarner

I was going to focus my efforts on creation of new pages that are needed. I figured I'd start with the Speech Synth since it's something I've been spending a lot of time with recently. Let me know if there's any specific needs for new pages, and I'll see what I can do. Thanks! Edit: Nevermind, I see there's already a speech page. It wasn't linked from some of the other pages, so I figured the page didn't exist. I guess I can go through and create links between pages wherever it's needed.

Sent my application to ninerpedia, mizapf. Took me a while to find the email confirmation message because it got sucked up in my spam folder.

I agree. His site has been my #1 resource ever since I discovered it, and he deserves the traffic if he plans to continue hosting it. I'll look into applying to ninerpedia.

I simply maintain everything I do as open source, across the board. That way, I don't have to deal with it.

I love the idea of a collective effort to maintain a wiki. I'm definitely game for being a regular contributor.

Anyone know how to get in touch with Thierry? I've got some web hosting and I could commit to long term hosting of a mirror, if he's ok with that.

Just an update to everybody who's wondering where I'm at with this project: I've gotten the revised boards in; I had to add a buffer chip between the PEB bus and the speech synth, to see if that would solve my issues with my first prototype. However, my forgetfulness bit me when I took a look through my inventory; I had spec'd out the chip to use way back when I did the redesign, but I realized I had failed to order any. Anyway, I got my parts on order, so I should be able to assemble the 2nd round of prototypes soon as they come in. I think I'm going to create a new official thread for this board whenever it comes time for the big run, to give everybody a chance to lock in their order, but I've got everyone's name written down who's expressed interest either on this thread or by PM, so I can be sure to make enough for everybody. The number is currently over 30 so far! I can't thank everybody enough for their interest in my project!

It's been my experience that HDX doesn't work well unless you're using a real serial port. The USB emulated serial ports tend to be dodgy. Don't know for certain if this is the case 100% of the time, but no USB to serial adapter has ever worked for me. If anyone else has had success using a USB to serial device, I'd be interested to know the model adapter you have.

Referred here from the Yahoo group. (Next node in linked list:) Found the Yahoo group via Google.

I don't wanna hijack this thread or anything, but when the time comes (and I feel ready to reveal them) I'll start a new thread.

In the past, I've considered what it would take to revamp the firehose connection, and I briefly visited wireless before realizing it would be a headache to implement and make sure the timings were exactly correct. My current idea is using a pair of MAX10 FPGA's, one on either side, sampling and serializing over LVDS with a shared clock to keep them synchronized. At minimum, it would require two twisted pairs (for full duplex), plus one more twisted pair for the clock signal. An ethernet cable would provide all the wiring needed, with one twisted pair left over. It's not a trivial project though. Getting reliable timing would be tricky. It'll be a long while before anybody can expect me to tackle a project like this, as I've lots of stuff lined up to do right after the speech adapter card is finished.

Modern "high brightness" LED's are gonna be glaring in comparison to the old-school LED's of the 80's and 90's. So if you are gonna have a mix of standard and high-brightness ones, be sure to stick a 1K or higher resistor on those high-brightness ones. I built a card solely for the purpose of testing CRU bits once, and I put an RGB LED on there, with each color hooked to a different CRU address. I wrote a program to cycle through the CRU bits, producing a rainbow of colors from my PEB. It's too bad I didn't take any video of it! I'll have to hook it back up one of these days and re-run the program so y'all can see it. It's pretty trippy.

Now can we get every permutation of combinations of chips from 2 to 7 out?

I've thought about an FPGA floppy controller, since I've been studying programmable logic as of late. However, what I'd expect in a product like this is full backward compatibility with the existing drive controllers, so that none of the software will need to be modified. What I am lacking is a fully documented description of those disk controller chips and their theories of operation. But if you could find something like that, theoretically, a disk controller could certainly be built in that manner.

The most effective way to produce a TI-99 replacement would be to program a system on a chip using an FPGA. Many other classic systems have been implemented on FPGA's, so there's no reason the same couldn't be done for the TI.

My guess is that one of the VRAM chips has gone bad. The standard fix for this these days is to install an F18A module. The side effect of this would be that you now get VGA output to boot!

SIMM's are dynamic RAM, or SDRAM (Synchronous Dynamic RAM) to be precise. They require some controller circuitry to dynamically refresh the cells. That would be a lot more complex of a circuit, since static RAM's can basically interface directly with the PEB Bus.

Ah, gotcha. Makes sense.

What's the key to those 74ABT series chips? Are those different from standard 74LS or 74HCT series?

That Y-adapter cable that I linked above.

There was a website selling exactly that: a Y-adapter ribbon cable to connect 2 PEB's. I believe this was the site: http://www.iec-usa.com/cgi-bin/iec/05MCOlderTI.html though I'm not sure if they still sell that cable. With a flex interface card in each peb, there's no reason why you can't have 2 peb's on one ti bus. Just be sure no two cards conflict on either address decoding or cru addresses. Edit: they do still carry that cable: http://www.iec-usa.com/cgi-bin/iec/L1173

The TI used IBM compatible drives, so I'd say yank those drives out of the PC and stick 'em in the PEB! Just pay attention to the Drive Select lines, and make sure you have your ribbon cable twisted appropriately so that on the TI side it's DSK0, and on the drive side it's drive B. (All PC disk drives are hard-wired to be disk B. Unless it's a REALLY early 5 1/4 drive, in which there's a jumper to configure it as drive A or B.) Double-sided should work with the original TI brand controller card, but to get double density or 80-track working, those would need an upgraded or modded controller card.

Sounds great! Thanks! I'll check Thierry's site to see if I'm lacking anything in the ol' parts bin. I think I have a 74LS612 stashed away somewhere from a long-ago abandoned attempt to build a SAMS clone. If I might ask, where are you sourcing your 612 memory mappers from? As I recall, I had a difficult time finding mine. Also, I have another question. Thierry's site shows that the HAMS can be used with up to 16 meg of SRAM chips. Considering the cost of purchasing that many chips, does your board have any provision for smaller configurations? For example, can I install 4 meg worth of chips, and configure the board appropriately to use that particular memory size?

I'm definitely interested. Is there a parts list somewhere so I can order all the necessary chips?

Thanks, mizapf. I enjoy learning some of the peculiarities of how this old hardware worked!