
Mcasm – A Microcode Assembler - jsnell
https://www.bedroomlan.org/projects/mcasm
======
hansihe
Funny, the microcode assembler for my toy-cpu which is written in newbie-
haskell is called the same thing.
[https://github.com/hansihe/ttl_cpu/blob/master/haskell/McAsm...](https://github.com/hansihe/ttl_cpu/blob/master/haskell/McAsm.hs)

This is an example of the syntax it has.
[https://github.com/hansihe/ttl_cpu/blob/master/microcode/mic...](https://github.com/hansihe/ttl_cpu/blob/master/microcode/microcode2.tmcs)

It, along with the assembler is configured through a yaml file.
[https://github.com/hansihe/ttl_cpu/blob/master/microcode/map...](https://github.com/hansihe/ttl_cpu/blob/master/microcode/mappings.yml)

If anyone is interested, there is an unfinished article about the project
located here. [http://hansihe.com/2016/11/25/i-built-a-computer-from-
scratc...](http://hansihe.com/2016/11/25/i-built-a-computer-from-scratch.html)

~~~
yosamino
From your article:

> If anyone is interested in seeing articles on those things as well, please
> tell me.

To which I'd like to respond: "Oh very much so! Please share!"

I've subscribed to your RSS feed, so you're sure to have at least one very
interested reader.

~~~
hansihe
Thanks! I'll see if I can get something more written soon. Is there anything
in particular you think I should prioritize?

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mmastrac
Has anyone attempted to fab a chip in an older process? I have wanted to build
a CPU for kicks, but it would be great to have real silicon rather than being
stuck on FPGA. I'd consider it reasonable if you could fab a CPU for <$2000 or
so.

~~~
YZF
Many years ago I worked on an electron beam lithography system that was a
converted electron microscope. You need to control the X/Y position of the
beam and need some sort of shutter/deflection mechanism which should be within
the realm of what a very dedicated hobbyist or group can do. I wrote the
software and designed some hardware. I wonder if you could pick up an old
electron microscope for cheap somewhere if that would be a starting point for
a home made chip fab ;) probably too many difficult parts though, wafers,
resist, bonding, packaging, clean room etc. But who knows, sometimes these
things can be done on the cheap if you're willing to make some compromises...

But here's another idea, if you live close to a university that teaches
semiconductor physics or chip design check with them, the system I worked on
was used by graduate students and for general research...

I don't think any fab will talk to you. A "real" chip is usually millions of
dollars even for older processes.

If you don't care about the actual fabrication then you can use programmable
logic like FPGA and get something very close to an actual chip design running
on an actual chip. You can probably just get a design to run in a simulator
...

~~~
DigitalJack
Check out MOSIS. They combine multiple small projects into a single reticle
set to spread the cost of a fab run.

Been a long time since I looked at it. No idea if they have a packaging
option.

~~~
femto
If you can couple up with a local academic institution, and get them to submit
your chip as a research or teaching project, MOSIS will fabricate your chip
for free [1]. They will package up to 5 chips, though it's not clear whether
the user or MOSIS pays that cost.

[1] [https://www.mosis.com/you-are/academic-
institutions](https://www.mosis.com/you-are/academic-institutions)

------
PhilWright
Unfortunately your talking about something like $100,000 to get custom silicon
made, even on an older node size. And you cannot get just 1, your minimum is
about 100. If you insist on just 1 then they will still make a 100 and just
throw the other 99 away, so you might as well get a 100 of them.

You cannot just throw some Verilog at the fab and get silicon back. You need
to use some very expensive software that generates and validates the actual
format they need. Hence you would go through a third-party company that
specialises in taking your Verilog and does the work needed to get it to the
point that the fab can make it.

~~~
stephen_g
There are some open source toolchains, such as Yosys [1] and Qflow [2] for
synthesising Verilog into ASIC designs that can be fabricated. And with multi-
project wafer fab services like CMP and MOSIS, fabrication can be had in the
tens of thousands of dollars for a few hundred ICs. So things aren't quite as
bad as you make it sound, but it's still a big investment and requires a lot
of fairly niche skills and experience.

1\. [http://www.clifford.at/yosys/](http://www.clifford.at/yosys/) 2\.
[http://opencircuitdesign.com/qflow/](http://opencircuitdesign.com/qflow/)

~~~
PhilWright
Thanks, I have not heard of those services.

