FarmerPotato

What the heck is that? Do you have that adapter?

PC Transfer: Mike Dodd (or Peter Hoddie?) wrote this tool to read TI floppies on a PC with floppy drive. I never tried it for writing to floppies. It required a 40-track floppy drive and media, no HD drives. Got the original package here.. but no PC with floppy drive. TI99PC is another one.

I can speak on the Kryoflux gear. It's a very capable device for retrieving old floppies. I've read a few hundred floppies with a TEAC 55B drive. With the Kryoflux you can save the raw flux to a file, and restore that to another floppy: it's a bit copier. Or you can ask for the raw tracks to be decoded from FM, MFM, (or other) and you'll get a file of the sectors in linear order, which I call a disk image. That file is ready to use with emulators. (Assuming you told it the right track order!) Kryoflux doesn't provide software to go the other way: putting a disk image back into the raw format. Or editing a few sectors of the raw file. So it's not a file transfer tool. It's a preservation tool. Nothing preventing anyone from writing that software--it's just bits. Gotek floppy emulator is the tool you want if you have disk images.

Hey, I just scanned my copy of the TM990/101MA revision H, Mar 1981. @Stuart's page has a scan of Rev D, Mar 1980, and part of May 1980. Posting mine here in this thread where it can be useful. Also, I made a new scan of the TM990/510/520/530 card cage and backplane manual. One of them is in color. I just like the yellowed paper background on my screen. I send the raw scans to Al at Bitsavers where he will use his process on them. MP341_TM990_510_520_530_Color_May80.pdfMP341_TM990_510_520_530_B_May80.pdfMP337_TM990_101MA_Mar81.pdf

I second @jedimatt42's idea. This is what I use. xdt99 runs the same on macOS or Windows with Cygwin. I also make use of "od -xa" to view files in hex.

A device that's sure to program TMS2716s is the TM990/302 software development board. I have not seen one for sale. I forget whether the TI-99/4A P-box card eprom programmer card did 2716. Probably not, I think it did only other single-voltage chips like the 2516, 2532. (Nick Hulbert added an adapter for 2764.) I see a lot of folks replacing non-TI 2716s with the 28C16 EEPROMs. Those would require a simple pin-socket adapter, and you could program them on a cheap TL866II or XGPro in a flash.

As you know, TMS2716s are not on the list. I was checking if my old PP3 could do TMS2716. Nope. Three voltages on it. But this article was fascinating: USB Pocket Programmer 3 FAQ: How EPROMs work Helps explain why EPROM programmers don't support old TMS2716s.

I learned out about the difficulty of programming 2716s by checking if my old PP3 could do it. Nope. This article was fascinating: USB Pocket Programmer 3 FAQ: How EPROMs work I'm going to have to make an adapter.

Then there is preserving documentation. @pixelpedant podcasts go a long way. Ftp.wh tech.com will one day turn the lights out--even though it has an amazing lifespan. DVD if anyone still has retro 2000s systems to read them on... Bitsavers... make sure to browse your TI sites through internet archive so it adds the pictures and subpages. I wonder if new documents are important to create. New stuff Manuals in pdf, not just web pages. ideally, if you bequeathed a pile of modified 99/4As then the heir (or estate sale buyer) would find instructions with it.

The way I've imagined multiple VDPs is further decoding the read/write address space. First hurdle, 8C02 and 8C12 are distinct VDPWA and writing to one does not clobber the other. Then, a cool feat would be to have GPLWS R15 point to one or the other. If the console software is consistent, then any VDP access is relative to this. You'd have to copy the original 16K to the other to keep GPL functioning. TI set guidelines for DSR authors to use the base addresses in GPLWS, not hard coded ones. That was to allow future consoles to have different memory mapped addresses. I wonder how consistently this was done? One might imagine moving the GPL environment to VDP2.. then running another program using VDP1, esp one that assumed 8c02.) Meanwhile VDP1 would just sit there statically, until you jumped back into it. You'd have to preserve PAD as well, so it would take a bit more Magic.

How would the console VDP RAM work? I guess the console VDP would need additional address decoding. Maybe a primary F18A in the console, with address restricted to 8x0x addressing, generating interrupts. Then a second VDP in P-Box at a different port?

Stuart, have you dealt with non-TI 2716s? I just read how TI had a different pinout, because 2716 required -12 and -5 supplies. If a different brand is used, at least A10 is on the wrong pin. My USB Pocket Programmer explains why it doesn't support TMS2716s. My 990/101MA has four TI TMS2716-45.

Hey, if you get both working, on the S-100 backplane, they can be used simultaneously. The PROM tells which addresses are off-board. I'm not familiar with the bus arbitration yet. (There's HOLD/HOLDA for DMA..) The floppy controller is a whole SBC too, with another 9900. It can DMA (access) to/from other memories on the bus. (Unless I'm mistaken)

Additionally, here are some part numbers. And I see some in stock at Digi-Key US or Mouser US. PC Card Edge receptacle, 50 position, 100 count, 0.125" (3.175mm) spacing. S-100 bus, and TM990 bus. TI also calls it T-Bus. Solder tail: EDAC. 346-100-526-802 (about $17 at Digikey) EDAC. 346-100-520-202. (about $19 at Mouser) Sullins. EBA50DRTH. (about $11 at Digikey) Sullins. EZA50DRTH. Not ROHS lead-free. I have observed EDAC connectors in an Altair 8800. (S-Bus) Right angle: EDAC. 346-100-559-300 ($11 at electronicsurplus.com) Sullins. EBA50DCBS. (about $11 at Digikey) Wirewrap: EDAC. 346-100-541-802 (not found) VAX/ELCO CORP - 4-215 ($11 at electronicsurplus.com) alternates VAX/ELCO CORP - 4-216 ($11 at electronicsurplus.com) alternates VAX/ELCO CORP - 4-176 ($11 at electronicsurplus.com) alternates GC Electronics 41-858/A7D50WW08A3 ($10 at electronicsurplus.com) GC Electronics 41-860/A7D50WW08A3 ($10 at electronicsurplus.com) PC Card Edge receptacle, 40 position, 80 count, 0.125" (3.175mm) spacing. Minicomputer 990 bus. 990 has two 40-position per slot. The CPU is always double-size (uses both), but some cards were single-size. Total of 160 traces on the backplane. Solder tail: Sullins. EBA40DRTH. Sullins. EZA40DRTH. Not ROHS lead-free. They don't list RT in the current data sheet, but you can order it. Sullins. EBA40DRSH. This is the current catalog ordering number for rows 0.25" (5.08mm) apart. Sullins Data sheet Current. Digikey https://s3.amazonaws.com/catalogspreads-pdf/PAGE68-69 .125 HP DS WW RA.pdf This is a monster 256 page pdf; searches take 20 seconds... 1995 Sullins catalog on bitsavers) Sullins Prefixes: Second letter, B or Z —The Sullins EBA series, ROHS, replaced EZA series tin/gold plated. Maybe the tin was not lead-free? B means 10mil gold plated. C is 30 mil gold. In the 1995 catalog it says Z was 10 mil gold plated tin, X 30 mil. Sullins Suffixes: D = dual RT, RY = old contact style, 0.14" (3.56mm) row spacing. (TI did not use this) RX, RJ = old contact style, 0.25" (3.56mm) row spacing. RS, = current contact style, 0.25" (5.08mm) row spacing. TK, CK = current for smaller holes H = End mount style: clearance holes, not threaded Ordering Digikey shows that to order a tray of 10 costs $79, takes 4 weeks. I've waited for a Sullins connector tray of 10 side-port 99/4A connectors before. I was pleased.

@smp Your understanding is correct. Restating what you already said: TIBUG is in left/right halves size 1K. Each half fills 000-03FF. Assembler output for address 0080 is found halfway into the separate file. TI 990 docs tend to count words, but it's clear about it. I do this for my own project: use "dd" to split the assembler/linker output into left and right halves.

@smp I'm glad you started this thread! I learned a lot from your questions. I did not realize that the S-100 backplane is a match!

Can't hurt to put in just the termination that TI has in their 4-slot. Just 3 signals I think? And pull-ups for RESTART.B and the like. Termination is not necessary for signal integrity on short traces. And 3 MHz is low speed. Should not matter at all, when you have only one card. Another thing, maybe not all traces go straight through. (Still those don't matter for just one card.) There may be lines that require jumpers at each slot. The 12-slot has resistors on many more traces. The trace length and the sockets each add more capacitance, making terminators necessary. From memory, I'll check sources later The Altair has 220 + 330 terminating resistor networks, in abundance. Anecdotally: these were the cheapest IC resistor networks in 1975. I looked at the Altair today. There are no terminating resistors. The S-100 bus has sockets in the center, so the card guides are wrong for the TM990, but that doesn't matter. I noticed a TMS8080A with date code 7819! TI uses slightly different values, but the idea is to terminate into the middle tap, to get 3V or anywhere above a TTL V_h_min, which is 2.0V--preferably 2.4.

Wow, that list is fascinating! The article that I found talks about those a bit--not successful, microprocessor era had just begun. Seeing this list, it puts the 76477 Complex Sound Generator in context. I have a soft spot for this WEIRD little sound chip. It lives on to appear in the 1982 catalog. The 76477 was used in the toy Sound Gizmo. The 1975 price list (scan coming next) has no 764xx yet. But the 76xxx range is all CON, defined as Consumer Integrated Circuits. (Exception: 76514 is LIN. But it has the same price as Linear IC 75514.) The 1975 price list is compact and doesn't have any chip descriptions.

I replied on that thread: found a 76410 mention. It was made in the Year of Pong. Still digging.

That 76430 rings a bell for me. I saw a TI application note for a "TV Terminal" that had a sync generator chip as part of a set. Might have been that. I found one mention of a 76410 in this story of the Pong-in-a-chip makers. IC Master (in Bitsavers) is another place to check. The 76430 gets one line in IC Master 1978. Go back a few years to when it first appeared, might reveal an application note. I scanned and posted the 1982 TI price list yesterday--definitely not in there. You can see a consumer electronics/TV theme in the remaining 76xxx chips.

Hey, I see the TMS7000 AMPL kits in the 1982 price list! See other thread

I got one thing done already for 2023, with Amanda doing lots of work next to me: Empty out small storage shed. Clean clean clean. Assemble 3 steel shelf units. Move every bit of computer stuff from garage to shed. More or less sorted! One shelf unit of TI stuff, one for Apple II & Mac, one for everything else. Next up in 2019: replace all the dodgy electrical wiring out there. Someday...

Teletypes didn't need bytes. Six bits was enough. So, 48 = 8 characters. You think bits grew on trees? Fred Brooks: "The most consequential decision I ever made was that a byte should be eight bits." (IBM OS/360)

Hmm. Not afraid to post ideas but I'm keeping the best ones to myself. * Begin fixed search pattern. * If tank in sight, find closest vertical or horizontal firing vector and move toward that. * If target sight is lost, continue anyway. Option: halfway there, stop, look left, then right. * Sneaky Smarts: if target is lost, predict its location, scan for obstacles. plot a box around the obstacle, follow box perimeter the opposite way round, intercept. If no recent information, resume search pattern.

Shall we make this thread our eBay heads-up thread for the subforum? I saw these for $250 which must be the TM990/102 extended memory CPU card. Pretty reasonable? Seller "expertsurplus" lists 10+ for sale. "Working when pulled." Title was just 1600287-000 PCB. They also have 10+ floppy controllers, TM990/303B for $175.