MrMartian

Well, like pretty much every other firmware I've seen, the density check is done while reading sector 1, and if there is an error then try after changing density.. That's why modern DOSes always read sector 1 before anything else. I'm guessing the 1050 US will do this on any sector, but then that would affect indicating bad sectors... A longer delay at least? Like the serial I/O, the front panel display is software controlled on these drives. Normally there is a timer IRQ that swaps which digit is being displayed, but when certain functions are going (like actual disk I/O, serial I/O, etc) where timing is critical, the IRQ is disabled. During sequential I/O then, the display only toggles between sectors. This is why it flickers more at U/S than normal. As for formatting, I could try toggling between each track but I think that would look odd as well. This is because the drive doesn't monitor the READY signal, so turning off the Atari makes the COMMAND line go low and the drive sits in a loop waiting for the command.. I could do more troubleshooting with multiple drives in the chain..

Well, only if you want to use the drive..

I don't remember, but most the whole ROM is rewritten as I made the whole read / write / format routines actually work.

My oldest programmer will even do 2708s and 2716s.. With the +/-5v and 25v. It's old and clunky and I need to keep an old DOS PC around for it, so I only get it out if I really really need to..

It's annoying, isn't it? I have three device programmers here now, from my various years of buying new ones and then finding out that I needed to keep the old one around to program 'that device'.. I have the original TL866 that does 21v programming. The newer TL866II only goes to 18v (which is what I'm guessing you have).. I could program a device and mail it to you, but I don't know how well things are getting across the border these days..

Yes, most 2732s likely need 21v (or higher).

Yeah no.. The 8031 is max 12mhz. And really, you're generally more limited to the overall system speed than raw CPU. I mean, I could go faster than a 52.6K baud rate on any of these drives I have done. I picked that speed for a couple reasons. 1) that's the original 1050 US speed (0x0A), most compatible 2) Speeding up the baud rate doesn't do anything if the sectors are still spaced the same apart. The Atari sends a sector request, the drive waits for that sector, reads it, sends it back. If the transfer went faster, then there would just be more wait until the next sector came along 3) We could figure out a different sector interleave and baud rate that would work higher, and then see if I can achieve that speed. That being said, do 'US Skew' formatters calculate the interleave to use based on the baud rate, or do they just use an interleave that they know works?

2732s for peripheral ROMs, 27128 for OS roms.. Or 27256 and you can switch two of them, 27512, switch four of them... I have a stash of ICT 27CX641 chips.. 8Kx8, 24 pin... Great for replacing BASIC roms and C64 roms... Don't know if you can still buy them anywhere though..

My code is much smaller, more optimized, etc... I stripped the copyright text but I guess I could put something back in listing the original copyright and mods by me...

If you could pull a copy of that ROM and compare it to any original image? Maybe you have another version?

All I can say is I have two here, one 6502 and one 8031, and neither have this issue. I had never heard of it until recently, but it does seem to affect some people.. <shrug> electronics....

Yeah, I often go back and curse myself trying to remember which file was which... I'm too used to small filenames. But, this should be 8031 as that's the chip (or 8051), not 8531 .. ??

Yes that one looks correct!

I'm trying to get the cart so I can dump it...

A friend just sent me these pictures.. Anyone ever seen something like this?

I wish more people would actually state this, as I think it would help adoption of people integrating these things into retro projects.. I still prefer to use Atmel CPLDs in anything I do because they are 5v devices.

Success! Just done up on a breadboard for now, and I used some 5v-3.3v level shifters... Which brings the question, the ESP32 isn't 5v tolerant... Are the 470 ohm resistors enough to limit the current so it doesn't damage things?

Thanks yeah, already got the software stack set up, built, installed.. Then found out I don't have any 470 ohm resistors.. I'll have to wait for those

Is it still possible to build and run this on an ESP32 dev board? I've read back through the thread and see people have but it's not clear how one would go about that.. With spare time on my hands, this could be good to look at!

You said this is modded with UAV? Perhaps there is a problem with one of the jumpers and you're missing one of the bits?

Do we have schematics of any of these boards?

I have a soft spot for TAZ!, obviously..

I've printed the tabs from this, and they work well. I haven't tried any of the other parts.. https://www.thingiverse.com/thing:3626730

I recently won another 600XL, and the first PAL 8 bit for me! I was happy to find out that one of my LCD monitors supports PAL so a overall a win! I do like the 600XL overall, it's quite easy to upgrade to 64K and then it's basically an 800XL in a slightly smaller footprint.

No, and having disassembled the ROM, there is nothing in there.