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Comment by kgwxd | Hacker News Reader

This is the coolest thing I've seen posted on HN in years, very cool work.

I've been playing with Atari 2600 programming on and off for the past few years and it is so fun programming directly against the specific hardware. I can't help but occasionally wonder if I could piece together a similar system, but I have 0 experience with electronics. I can only imagine how satisfying it must be to actually pull it off.

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Thanks a lot :)

It really is super satisfying to get this far, I still turn it on sometimes just to check if it really works.

And I also had zero experience with electronics (and I still don't know as much as I should...), so yeah I think you could piece together something like this. :)

I was a tad skeptical when I saw the title. But it looks like you really pulled it off. It took Atari engineers like 4 years ;)

Is it fast enough for multi-input / multi-player?

Thanks :)

The only multi-input game I have right now is Tetris for 2 players. My girlfriend doesn't complaint while playing it (except when I win :P), so I'd say it's pretty responsive, even with the somewhat convoluted way the CPU communicates with the PPU and the double-buffering.

I think it will work for other types of games as well. With all the hardware, firmware for the 3 microcontrollers, bootloader software, compiler toolchain and tools, I still haven't gotten around to actually make a lot of games for it.

This is crazy dude! You're an inspiration! Awesome job!

I would totally pay (~$300) to jump on a pre-packaged MOOC like course that has a batch of students working together and the course fee would include the hardware needed and access to a TA like resource (when the batch of students can't solve a problem together).

I can even imagine a part II with modern components after learning this level of basics.

Wow! Thanks for making such an interesting and detailed writeup! And using my favorite CPU too :) Definitely bookmarked to read through more times.

Z80 rules!

Thanks :)

I love that there is a group of people who still love the Z80!

Such a beautifully designed chip.

I was doing a little bit of Z80 work a while back, but I didn't particularly seem to appreciate its design (compared to say MIPS). Why do you think it's beautifully designed?

You can hand clock a Z80. There is a certain magic to that.

I'm sorry, but what does "hand clocking" a Z80 mean?

I think GP's use of "hand-clocking" to refer to the factthat the z80 can run on a very low clock rate, to the extent that you can have a hand switch that sends individual clock pulses to the processor. This can be useful for testing purposes as well as for low power operation in embedded applications.

http://www.thomasloven.com/blog/2013/01/Z80-Tester/

As the Z80 doesn't use dynamic registers (I think basically the only "modern" CPU to make this decision) it doesn't need a minimum clock signal speed to refresh the registers as every other CPU does.

This means you can rig up a push button switch and manually advanced the clock one button press at a time.

To me that's super cool. It also makes them really easy to debug.

Admittedly, I do not have a lot of experience in other CPUs, but to me its just the way its designed. A simple syntax for assembly and the way it maps to byte values is clever. It doesn't require a lot of work to make things happen, ie "hacks" for interacting with IO. I also like how there is a separate IO bus from the data bus, which means IO doesn't take up memory. The register naming convention is simple, and having "alternate" registers is cool.

Just seems simple and cool to me.

Out of curiosity, have you thought about trying to port "real" games over to it, as in running a ROM of something commercially released? This is already really cool, but it would be nerd-cred-for-life cool if you could say "Oh, you have a gameboy? Yeah, I built my own."

I used to do Z80 programming in the TI-82 in high school back in 2002. This seeing the code in the article brought back some good memories.

Awesome work, dude!

> I still turn it on sometimes just to check if it really works.

I know that feeling ;)

Just ordered Make: Electronics and a cheap electronics starter kit with a breadboard and some basic components. Thanks for the inspiration.

You should check out Adafruit and Sparkfun as well. They have a lot of solid tutorials to get you started, and a bunch of inexpensive microcontrollers that are easy to get going with, as well as all sorts of lights and sensers and switches to connect to them.

> I still turn it on sometimes just to check if it really works.

I feel this on a personal level, albeit on my much smaller, less complicated projects. Thanks for the amazing write-up, you are an inspiration to us all.

There is something weirdly satisfying about doing something purely for the sake of doing it. So many people start projects hoping they can turn it into a business or gain stars in Github - you see less and less people hacking stuff together just for personal enjoyment.

I think we need more of that too. Everyone seems to be on a quest for perfection: perfect code, 3D printed casing, everything intellectualised to the nth degree. There's a lot to be said for the "rough and ready" approach of experimentation. However to do that you really need to be on a pursuit for personal gratification because the internet is a harsh bitch for pointing out ones mistakes.

“One’s mistakes.”

Agreed, this is dank. The successful wiring alone is noteworthy.

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