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I plan to build a home brew minicomputer using just TTL ICs.(no x86,no FPGA)
Didn,t come up with the initial plan right now.But I do think that home brew minicomputers can take home brew OSes to new levels......

What do you think of it?

Personally, I think with the Raspberry Pi on the horizon, the need for homebrewed hardware has sharply diminished...

I mainly wanted to build this for learning,but plan to build the second major revision on a few FPGAs.(which would make it much smaller.)
And whats the problem with homebrew hardware?You could easily market a fast FPGA computer....

Hi,

Solar wrote:...Raspberry Pi...

Didn't know abou this device - thanks for the info! I want one!

@op: Sounds like a huge amount of work (hobby computer and hobby OS), but there are a few designs about. If you haven't already seen it, have a look at HomeBrewCPU

Cheers,
Adam

Just another link to "homebrew minicomputers": The scraputer. I recently found the link here on the forum.

The only thing I don't like about the Raspberry Pi is that it uses the proprietary BCM2835, for which there is no publicly available datasheet, pinout, register description and so on. Some functions work only with licensed, closed-source drivers. This seems to be Broadcom's general philosophy. But I guess as soon as the device is out there and running Linux, people will start to figure out how things work... Happy hardware hacking.

Look out, it's hard to build a homebrew mini computer with just ttl-logic, you'll need a good plan and allot of patience, and you'll need to solder allot without making to much mistakes, and if you want to make one that is decent enough for running a basic hobby OS(i.e. have some sort of screen, memory, eprom, and some I/O support for a keypad or something) you'll need an insane amount of free time. And this is only when you use a RAM chip or flipflops, if you want to go really hardcore and design the RAM only using logic gates: it's around 5 to 10 gates for a good flipflop, so if you would like 100 bytes of RAM that's 4000 to 8000 logic gates, and then you'll need some sort of bus...

I advise you to start of with building a z80 computer from scratch, or designing your cpu directly on FPGA's.

berkus wrote:

dictionary wrote: allot |əˈlät| verb
give or apportion (something) to someone as a share or task

Indeed, but at least he's made the effort to use a real word rather than the common alot.

Legendmythe wrote: I advise you to start of with building a z80 computer from scratch, or designing your cpu directly on FPGA's.

Been there, done that, got the T-shirt.

Plan to build it on FPGAs now.ISA is finished,I am going to scan it now and upload it.277 instructions in total.

berkus wrote:Doesn't fit a byte, it seems

One could say: It's a bit too much.

As a random project I started a couple of years back, I made a dumbed down version of VHDL I called LogicCircuit, and started designing a CPU in it. I've recently managed to get my 32-bit edition of it working (well... with the ALU only)

Link: https://github.com/thepowersgang/logiccircuit

My next trick once it's designed is to locate the places where I still assume the timing will be atomic, remove them then try and plan out a circuit for it (with clocking to give timing points)

@thepowersgang
I think you might already know this but your CPU32 implementation is lacking CPU32 support.
I know i know it's bad taste to make such jokes, but be careful with names, all the cool and simple one's have already been taken at this point.

And its 277 without the logical instructions(I was too sleepy at that point).So I'm redesigning it.