Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Way over my head in awesome project

Status
Not open for further replies.

Klone38

New Member
I want to make a fully functional 1980's style computer like the Apple II or something to that effect for all the gloryous geek nostalgia value.

but as an added twist, type in something to the console window and it boots a hard drive containing a real OS like Windows or Linux or something like that.

I want to lay out a schmatic and have it fabbed custom so i need to know stuff like what kind of chips and processors to use to make it work.

If anybody has any ideas about this please help out.

I expecially need help on how to wire up a Intel processer
Or
I make a board that has all of the regular old computer functions and on command, the board turns on a prebuilt motherboard and turns all control to it. :confused:

Any ideas are accepted :D
 
The question that springs to mind is WHY?

However, just use a normal PC running windows and an emulator.

Mike.
 
I want to lay out a schmatic and have it fabbed custom so i need to know stuff like what kind of chips and processors to use to make it work.
If you need to ask what kind of "stuff" goes in a computer then you are indeed in "Way Over Your Head..."
 
Last edited:
Hello there,

I designed an built a number of mother boards using older style CPUs and although they are interesting they are only useful for controlling stuff and things like that, and even then it's a bit of an overkill. With a board 4x6 inches you can build a Z80 based computer MoBo that can control stuff and if you like you can write an OS for it and connect to some kind of display. It's quite a job though.
I've also built a motherboard out of discrete logic chips like the 7400 series with some programmable memory like the old UVEPROMs and it is interesting but only useful for controller type apps and it requires quite a bit of board space so you have to ask if it is really worth it in this day and age.

I've got a TRS80 sitting here too with an OS that boots into a whopping 64k bytes of memory (yes that is kilobytes not megabytes) and a word processor application that runs that space too. It's a Z80 based design too.

Does anyone remember the Sinclair with its 16k of ram? I've got one somewhere ha ha. That's Z80 based too. The Z80 is a little simpler design than using the 8080 or something like that.
 
I want to lay out a schmatic and have it fabbed custom so i need to know stuff like what kind of chips and processors to use to make it work.

I do not mean this to be unkind - but you don't have a single clue as to what you are doing. Do you understand the concepts of buses, addressing, address decoding, memory mapping, peripheral interfaces, registers, and on, and on, and on...? If not, then your first trip is -not- to the parts bin, the electronics store, or the PCB fabrication facility: It is to the library (or more likely nowadays, the used/antique/rare book dealer).

If you are serious about pursuing this project, first off you need to be prepared to spend a lot of time and money. Depending on how you approach the project, the parts alone will easily outstrip the costs of a new PC, mainly because you will be dealing mostly with parts that are surplus, new-old-stock (NOS), and in some cases, collector items ($$$). Many of the parts needed haven't been manufactured in over a decade or more. You will likely need to deal with collectors who will want a lot of money for certain prized parts (if they will part with them at all). Beyond the costs, though, the amount of time needed to pursue the project will be staggeringly large as well; this isn't a weekend project. Starting from zero knowledge, it will likely take you a year (minimum) just to get up to speed on basics, and then another 1-3 years planning your architecture, and perhaps building prototypes. The "final" (in this kind of project, nothing is really "final") version will take about 6 months to a year to assemble and debug. Note that a lot of this depends on your skill with electronics and digital design; I am assumming a fairly good proficiency with my numbers. After you have something working, then you have to figure out how to get code on the thing (and an operating system? you won't get Linux or something like that on it - you might be able to get something like CP/M or Flex, or something like that running - and if you are building that from scratch - well, good luck).

You could easily dedicate a good chunk of your life to such a project - seriously; this isn't a project for the "faint of heart". If it is something you truely feel dedicated to do; a passion, if you will - then good luck, it will be a very rewarding (and trying at times) endeavor. You will gain a level of understanding of computers and the pioneers that built them in a way few do and have.

Finally - books: You are going to want to find a catalog listing, if you can, of the publisher "TAB Books" - these are long out of print; if you need, I can reccommend a few I have in my collection (I by no means have all of them or even the best of them - but I have quite a few that could be helpful - PM me). TAB was a publisher in the 1970s and 1980s of technical books; "How to Build Your Own Working Microcomputer" and titles of that nature (In fact, I believe that is one of the titles - the author's name, though, I don't remember, but I think it is in my collection). These were books that were written by a myriad of various authors, detailing all kinds of techinical topics; many of them on popular pursuits of the period: Alternative energy, lasers, hifi audio and speaker constuction, robotics, computers, software and programming, etc. They all were published with a similar style and layout - it was a very concise and detailed, yet very easy to understand and follow, for the most part. Since the style was so consistent, from book to book, if you read one TAB book, you were versed to read the others easily. Its something you don't see today (the closest I have seen has been the O'Reilly series of books).

Good luck on your pursuit.
 
Klone, regardless of all this chatter beforehand, do you understand that you can still actually buy these computers? Authentic ones not remakes.
 
Also, do you realize, that you can stuff all the guts from a modern compact PC, into the case of one of those old computers. And as mentioned above, you can get an emulator off the internet, for most of those old machines. I have a small GPS, that run Windows CE, and unlocked, it runs several other applications and games... Recreating one of those old computers would take a lot of time and money, and wouldn't be of much practical use or interest, beyond a hobby, and you did it. Might check on Hackaday.com, remember seeing similar projects...
 
Klone, regardless of all this chatter beforehand, do you understand that you can still actually buy these computers? Authentic ones not remakes.

Something to keep in mind: A lot of these older machines are -rapidly- increasing in value to collectors (and aging people of my generation longing for the "old days" - ahem); some of them (depending on their condition) are waaaay out of the price range of most people (I always like to tell about my $100.00 Altair - I got super lucky). Even Apple IIe are starting to increase in value, when at one point you couldn't even give them away (of course, the 5.25 inch floppies on those old beasts were craptastic - they had more plastic than metal in 'em; you had to go with a TRS-80 and a few others to get quality floppy drives - and even those are getting hard to come by in any working condition; then there is the trouble with finding blanks).

Honestly, getting into any sort of antique microcomputer system is starting to become difficult - the collectors and antique market know the value of these things, and it isn't going down. If you are lucky, you might find something out there going for cheap (it happens - always will), but you gotta know what you are getting beforehand.

Besides which - I don't think that's the point here; I think the OP wants to try his hand at the "old school" ways. Others have done similar (plenty of others - heck, I even know of a couple of people on the 'net who've built relay-based computers). I don't think the OP is really ready for it, yet - but if he is serious about trying, there is plenty of info out there to help, still.

As far as stuffing the guts of a new machine into an old case, HarveyH42, that only of consideration if the donor machine is a "case only" or has no other redeemable value. I think you would be daft to do something like rip the guts out of an early Mac, or a old Lisa, or an Apple IIe (or heaven forbid a Sol or Altair, or other old S-100 bus machine!); you could likely hang onto it for 10 more years and have a nice investment machine.

Then again - maybe I should be encouraging this sort of destruction - it'll just make my collection more valuable...
 
I've got a TRS80 sitting here too with an OS that boots into a whopping 64k bytes of memory (yes that is kilobytes not megabytes) and a word processor application that runs that space too. It's a Z80 based design too.

Does anyone remember the Sinclair with its 16k of ram? I've got one somewhere ha ha. That's Z80 based too. The Z80 is a little simpler design than using the 8080 or something like that.

64Kbytes of RAM is quite a lot. My first "Trash80" had 16KBytes. I purchased another 32Kbytes RAM extension costing a small fortune and another small fortune for a chipset enabling the "computer" to display lower case letters.

My little niece had quite some experience with the Sinclair Z80. She typed in a question and the machine answered: "SYNTAX ERROR". She replied: "What do you mean?" Answer again: "SYNTAX ERROR" :D

Boncuk
 
My little niece had quite some experience with the Sinclair Z80. She typed in a question and the machine answered: "SYNTAX ERROR". She replied: "What do you mean?" Answer again: "SYNTAX ERROR"

Boncuk, while I certainly don't agree with you on everything - that brought a smile to my face...
 
Boncuk, while I certainly don't agree with you on everything - that brought a smile to my face...

Glad to know you are able to smile. :)

BTW, I also don't agree with everything you post, but we are all individuals - no machines.

Regards

Boncuk
 
64Kbytes of RAM is quite a lot. My first "Trash80" had 16KBytes. I purchased another 32Kbytes RAM extension costing a small fortune and another small fortune for a chipset enabling the "computer" to display lower case letters.

My little niece had quite some experience with the Sinclair Z80. She typed in a question and the machine answered: "SYNTAX ERROR". She replied: "What do you mean?" Answer again: "SYNTAX ERROR" :D

Boncuk

Hi,


Oh ok, well mine came with 64k with the option of getting another 64k (which i never got) and also an optional graphics card that would display single color (green) graphics (never got that either). It was a 'portable' model too, with a small (green) CRT screen about 8x8 inches which was built into the computer along with two 5.25 inch floppies. The OS would boot from floppy when you turned it on. Was a cute machine really.
I got a computer language disk with 'BASIC' on it but it did not have double precision trig functions so i had to buy a disk with routines on it to do that so i could do circuit analysis.
 
Last edited:
You guys with your ready-made appliance computers, you had it easy! My first computer had 256 bytes of RAM and I was happy to have it. When your only program entry method is a row of toggle switches, you don't yearn for more. My first program was a game, where one LED in the row would light and chase up and down the row on my front panel and you had to flick a toggle switch under that LED at exactly the same time as that lamp was lit. Ah, good times.

After some time, I was able to add 1K and later 4K of RAM. My first operating monitor program (can't really call it an operating system yet, its just too small) was an adaptation of something called "CUTER" from Processor Technology, based on storage on cassette tape. This data storage method was somewhat unreliable. I used the S-100 "standard" as my base so that I could buy some boards and build others as needed. I used that computer for over 4 years, for all kinds of things but mostly writing papers for school assignments. It eventually expanded with an 8 inch floppy disk, CP/M operating system (with my own I/O drivers), and 64K of RAM. I even had a printer eventually, although it only handled Baudot code which was a 5 bit pre-cursor to ascii. It was a model 15 Teletype and man did it shake the floor. Those were simpler times indeed.
 
Guys, if you have the chance, check out "Retro Computing on an FPGA" in the Dec, 2009 issue of Circuit Cellar. The guy did just what the OP is talking about.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top