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>> I might be in the minority but I hate Github. And I'm not particularly thrilled with their terms and conditions, which allowed for >> them to train AI models against the data and code. Remember, if you are not paying for the product then you are the product. I'm with you, Mike. Too...

Hi Paul, I'm not sure I understand your question, so please forgive me if I end up "in the weeds". The 68000 uses an exception table that must start at address zero. It is $400 in length, and contains vectors to processes that handle system requirements. A large part of that table (vectors...

Probably SRAM was for any scratch storage needed by the operational code? I don't think I ever got, or saw, the soft/firmware that went with the PBUFF hardware.

Here's what I got.

Sure .... I can scan what I have. They are kind of disorganized, and very short on written explanation. But the schematics look very good. You are right -- lots of revisions. I got rev. K. It was a long time ago, but I seem to remember that he was selling out of the print buffer stuff, and I...

There was a guy in Australia (Don McKenzie ("Dontronics") ) who did a printer "buffer" ("PBUFF"). I still have the (unpopulated) PCBs and documentation for the thing. I was going to try to re-purpose it for a general purpose Z80, but never got around to it. Looks like it could use 1 MB(!) of...

As a follow-up to my post above, I used the same basic design but with a FreeScale MC68SEC000FU20 CPU. I find soldering TQFP .8mm parts very <ahem> challenging, but my friend is a soldering whiz. He provided me with the CPU on an adapter board (thanks Johan!) that I used as sort of a daughter...

Never mind, Scott -- I just tried to dump those ROMs. Three appear to be empty (erased), and the 4th has what seems to be Z80 code on it. I guess I re-purposed those ROMs long ago, and the original content is lost to the ages. *frown* Roger

Scott- Years ago I worked on an employer's voice recognition project, and had access to a Rockwell AIM(?) computer. I still have four 2732's that are copies of some of the firmware from that computer. I didn't even have the presence of mind to mark the 4 ROMs, so it might be a jigsaw puzzle...

Hi Malfer, If you can find a copy of the paperback book "Z80 Applications", by James Coffron, chapter 8 has very specific information about the Z80 PIO, including initialization code samples. There are sections for all four modes of the PIO (output, input, bi-directional, and non-handshake...

This item has been sold.

For sale: Magnolia Micro floppy controller for Heath -- $50. Includes prototype board and connectors. Free shipping to U.S. only.

>> (I mean Chuckwagon is still slinging burgers, or was last time I checked a few years ago) Still there!!! Roger

Would you be interested in building a small SBC yourself? The attached photo is of my Z80 CP/M homebrew computer. It can be powered off of the USB console port. It has sixteen 8 MB "drives" on a compact flash module. It runs CP/M at 20 MHz, and has two serial ports running at 115.2k baud...

Hi Doug, I see you have an interest in Magnolia Micro. I have a MM floppy controller card for the H89 (I think -- that's what Herb J. told me).I don't know anything about Heath gear. I'm wondering if I might be able to sell it, and where I can list it for sale? I'd rather not mess with ePay...

Yes, Plasmo, it is an 18.432 oscillator. I didn't try anything faster because the SRAM is marked 55 n.s. Good to know that it might be able to be powered from USB, bsd64. If you play around with the Z180, you'll soon learn that the on-chip serial is a bit "funky". The IN/OUT opcode using the...

>> This is the FORTH curse. Everyone writes their own and marvels at, but nobody uses FORTH for anything but writing FORTHs. Somebody should have told SUN that. *grin* I believe that their boot firmware for lots of the SPARC architectures was written in 4th. I have a copy of it somewhere...

Here's my homebrew version of the Z-180 design by Stephen Cousins (SC-131). It's very small -- fits on a 100mm x 100mm PCB. It could be lots smaller, but I added some footprints for alternative EEPROM that I wanted to experiment with. Right now it runs with a PDIP Winbond W27C512 (64k) in a...

Thanks for the pointer to MINCE, Chuck. I had heard of it, but was not acquainted. I see that there's a site on Git for PMINCE (portable MINCE). It's available for the Zilog family AND 68k! Added bonus because I have a number of Z80 and 68k homebrew SBC's. I downloaded the code, so now have...

I've spent a lot of time trying to get Ralph Betza's version of EMACS working with a VT100 terminal, but so far have been unsuccessful. It looks like his code is set up to work with either an "ASCII" terminal or an "ANSI" terminal (his terms). Setting it for "ANSI" doesn't work. I can see...