[HN Gopher] Connecting an 8086 or 8088 processor to a Raspberry Pi
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       Connecting an 8086 or 8088 processor to a Raspberry Pi
        
       Author : tadbit
       Score  : 63 points
       Date   : 2022-05-20 14:55 UTC (8 hours ago)
        
 (HTM) web link (www.homebrew8088.com)
 (TXT) w3m dump (www.homebrew8088.com)
        
       | phaedrus wrote:
       | I did a similar thing with a 6502 and the Propeller
       | microcontroller. I always meant to make an 8086 or 8088 version,
       | but moved on to other things before ever doing so.
       | 
       | Dangerous Prototypes wrote up a pretty good post about it:
       | http://dangerousprototypes.com/blog/2012/02/22/prop-6502-pro...
        
         | redundantly wrote:
         | The Parallax page they link to is gone, archive.org doesn't
         | have any of the pictures/videos of it.
         | 
         | Do you happen to still have this information somewhere?
        
           | phaedrus wrote:
           | There's more pictures and info on my old blog:
           | 
           | http://dennisferron.blogspot.com/2008/12/prop6502-laptop-
           | pro...
           | 
           | Looks like Parallax still has a link to their old site, but I
           | couldn't find the contest pages there, either.
           | 
           | https://www1.parallax.com/
           | 
           | I'm pretty sure the code I wrote for it ended up on the
           | Propeller object exchange, but _that_ site also is gone... It
           | probably lives on in the migration to a github repo, but it
           | isn 't so easy to search by author AFAICT.
           | 
           | http://obex.parallax.com/
           | 
           | My picture (along with the other design contest winners and
           | honorable mentions) was on the back of the May 2009 Nuts and
           | Volts magazine, but I just checked my copy and there's no
           | article inside, just the blurb on the back cover.
        
             | tadbit wrote:
             | Thank you!
        
       | morpheos137 wrote:
       | shouldn't this be trivially simple with an rs232 to usb adapter?
        
       | trollied wrote:
       | Reminds me of the project that used a Raspberry Pi running a
       | software emulator as an Amiga CPU - Pi plugged into the CPU
       | socket via an adapter board. Probably the most impressive project
       | I've ever seen. https://www.hackster.io/news/hands-on-with-the-
       | pistorm-the-u...
        
         | reaperducer wrote:
         | Lots of interesting drop-in chip replacements in the retro
         | computing world these days.
         | 
         | Two I can think of off the top of my head:
         | 
         | - FPGA 6581 to replace a Commodore 64 SID chip.
         | 
         | - There's a drop-in sorta Z-80 so you can run CP/M on the
         | TRS-80 Model 100.
        
           | Terry_Roll wrote:
           | I wonder if we might see drop in replacements used in other
           | tech from the past that might be end of life or near to,
           | especially space satellites where power supplies permit.
        
             | sigstoat wrote:
             | space hardware doesn't involve a lot of socketed parts.
             | 
             | and end of life usually means battery or mechanical
             | failures, not "the electronics need an upgrade"
        
         | LeoPanthera wrote:
         | There's a similar project for the Acorn BBC Micro called
         | PiTubeDirect, which allows the Pi to emulate several different
         | CPUs, while connected to the BBC Micro's "tube" second
         | processor slot.
         | 
         | https://github.com/hoglet67/PiTubeDirect
         | 
         | (The BBC Micro itself was quite remarkable for supporting
         | multiple processors, which did not have to be the same
         | architecture as the host 6502. Amazing for 1981.)
        
         | metadat wrote:
         | This seems worthy of its own HN submission, so I did it:
         | 
         | https://news.ycombinator.com/item?id=31449828
        
       | tpmx wrote:
       | Love the simple/elegant/powerful idea of driving the CPU clock
       | from code running on RPI/Linux. It sidesteps the difficulty of
       | efficiently doing bitbanging on RPI/Linux in a neat way.
        
         | jesuslop wrote:
         | The idea is fantastic. It would make a great computer
         | architecture lab asignment.
        
           | tpmx wrote:
           | Yeah, you get a way of easily doing a GUI via HDMI or X over
           | IP or whatever, much easier development for most people and
           | lose some performance you don't really care about anyway in
           | that situation.
        
       | wila wrote:
       | Had to search for the PCB. Looks like this is the one:
       | 
       | https://www.ebay.com/sch/emil6190/m.html
        
         | tadbit wrote:
         | Correct! I recently ordered the 8086 version (the first CPU I
         | used as a child) so I could play around with it.
        
       | dboreham wrote:
       | Confused as to why this is a useful exercise vs emulating the
       | 8086 on the Pi?
        
         | [deleted]
        
         | synu wrote:
         | Perhaps it's more to see if they can, or for fun, than strictly
         | for some useful purpose.
        
         | VLM wrote:
         | This is a sort-deep link to one page of the site and the main
         | page of the site explains the overall project to design and
         | build one's own XT-clone. Kind of ambitious.
         | 
         | So start with a Pi running around 1/30th normal speed, then get
         | the memory card working and remove that from the pi, then get
         | the video and BIOS support working and remove that from the pi,
         | eventually remove the last thing from the pi and crank the
         | speed up about 30-times faster and you've got a gradually
         | bootstrapped fully operational XT-clone.
         | 
         | Its an interesting project plan, usually people bring up a
         | system by having just CPU and memory at least partially
         | working, then add peripherals like disk, display, rs232, GPIO,
         | etc. But this way you can bring it all up, at least enough to
         | run CP/M (err, ms-dos I guess?), admittedly glacially slowly
         | and mostly emulated, and then upgrade the parts to hardware as
         | see fit.
         | 
         | Could probably do something with a FPGA that would be much more
         | difficult but could at least run full speed (or maybe faster?).
         | Of course in early 2022 what's more unobtanium, RasPis or
         | FPGAs? If you can't buy either I guess it doesn't matter.
        
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       (page generated 2022-05-20 23:01 UTC)