MrMartian

Yes, Return shows the correct key in Self Test. It's not the keyboard, it's whatever happens when you hit Return, and basic tries to parse the line.

The OP doesn't have a drive, but I do. If Lucas still can't figure it out and wants to bring it back to me, I will try more.. As for chips, everything was replaced.. So, it's got to be a trace issue on the board, either a short or open. I was trying to think of an OS or something that I could put in to do some memory probing, but my EPROM program was unusable due to Windows being borked... Ah well.

I agree. The PL2303 is bad. Only use FTDI USB-Serial...

PIA was replaced, all RAM was replaced. I've really got to start writing more before posting.. Ah well, that's why edit is here. It really seems to be more of an addressing issue than a direct IC issue. XL self test shows good, SALT RAM test shows good, and the fact that a number of things work make it really odd what is happening. Does anyone know of a memory test that actually tests addressing? IE; not just that I can write $00 or $FF, but if I write $01 at $0100, and $02 at $0200, $03 at $0300, etc, and then check that those values are still at those locations? If not, sounds likes something that could be written..

Update: Tried MMU, DRAM muxes, etc, nothing fixed it. It's definitely a memory addressing / corruption issue. Basic XL gives error -14 when hitting enter. Mac/65 gives an inverse-heart symbol, syntax error. It's almost as if it's parsing from the wrong memory area. Edit: Forgot to mention that I also tried loading games from disc.. Ballblazer came up and looks normal, Zorro booted and played music, but the screen was corrupted... ??? Any other ideas?

No, it did not.

I was reading this thread and wishing it had come up when I had Larry's 6502 Rana board here when I was working on the US ROM... Well, I found the board here so I guess I forgot to send it back! (Sorry Larry!) Looking at the board, I do see a spot for a 26 pin header, and a socket for the LS374. I can guarantee that there was never code in the ROM to support a printer device. I can only assume they thought to put it in as the Trak drives at the time had one.. I could write it into the code, and stuff the parts, but I have no way to test that as I don't have a parallel port printer anywhere!

I like this idea. Especially since I need a 1050 belt or two, but the shipping on just that is quite high!

I'm in Woodstock, and have many spare chips.

I'm trying to compile this on FreeBSD, but I can't find software that compiles PEG. Do you know what the actual software is that you use on linux?

Due to the support for virtual memory, the stack was also different when interrupts were triggered. I'm really wishing I hadn't given away all my ST stuff a few years back, as I looked into this back in the early 90's after seeing that same AN (which I still have). I did spend a lot of time investigating this. Perhaps you could send me your logic equations and I'll see if I notice anything. Reading your descriptions of DSACK0/1 reminds me that there was a problem with byte access, as the 68000 just used the upper or lower 8 bits, but the 68020 always did 16 bits and I though you had to shift which way the byte went? Time to pull out my books!

Too bad there's a border in the way - I'd be wiling to do the work...

I'll take one! I'll probably also take a look at producing some for other Canadians, once I see the plans..

That won't work, if for no other reason that OS-B clears port B's bits which turns off the OS.. There was an XLFIX OS that work when I flashed it into my U1Mb. I got it from here somewhere...

What I used was an old CD audio cable for a PC, which I had a box full of......

It does 2764 and 27128 for sure, and some 2732. It will only generate 21v VPP, not 25v...

Current non-users wish we could buy one!

So, it can write to a disk, but not format it? That doesn't make any sense... Formatting is no different than writing a sector, just a track at a time...

Sounds like another challenge for me... I've briefly looked through the ATR code, will have to check it again...

They are used for both resistors and capacitors... https://en.wikipedia.org/wiki/Electronic_color_code

And it looks like a standard 6502, not a Sally... ????

When I had my original 600XL back when, I also had a 1064... Maybe they only sold them in Canada?

Ditto....

Top drive is an actual option.. Not meaning the highest number drive..

The TL866CS, also a $50 programmer, does fairly well and does basic GALs..