
DAN64, an AVR based 8-bit microcomputer - bjoko
https://www.usebox.net/jjm/dan64/
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jcoffland
This is a really cool project. I do a ton of AVR programming. They are
fantastic chips.

A lot of people think because AVRs are 8-bit, they are just toys. And since
ARM cortex processors are about the same price, that AVRs are not a good
choice.

AVRs, like ARM Cortex, are SOCs (System On a Chip) but have really excellent
peripheral devices compared to the ARM Cortex I've used. The AVR's internals
are better documented, more consistent, more powerful and easier to use. The
AtXmegas in particular, with their hardware event system and DMA controller.

ARMs have all the same peripherals but they are not as well thought out.
However, if you need to do a lot of 32-bit math, ARM is a better option.

Edit: Note that a 32MHz atxmega AVR can do about 128k 32-bit floating-point
multiplys per second.

~~~
emilfihlman
There are ~four things that matter when developing product hardware:

Capability, cost, design and firmware: is the hardware/firmware combination
capable of what you want, how much is the bill of materials, how laborious is
designing the hardware (schematic and routing) and how easy and fast is it to
develop on the system.

_Nothing_ so far has AVRs beat on the last aspect and they fare very well on
the third also. And this is a shame, because similar development ease and LibC
style is something that other vendors could very, very easily reproduce but
are stuck up on forcing vendor lock-in and pushing their ever shittier IDEs on
you.

However AVRs almost always lose on 1 and 2, especially compared to ARMs, which
are just better in almost every way.

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reidrac
Author here. Nice to see this on HN again. Since the first time, the design
has been validated by another hobbyist (and ported to NTSC, original composite
video is PAL).

If anyone is interested, I have a NTSC patch that I've meaning to merge for a
while.

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AnIdiotOnTheNet
I've wanted to do a project like this for a while, but always seem to have too
many higher priority things going on. There's something undeniably romantic
about building your own personal computer in this fashion.

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pdimitar
Some questions:

\- How can I buy this one already assembled?

\- Can it be put in a very silent case but still with a fan so as to not
overheat?

\- Can I use another display? (With the same technical characteristics but
possibly less training on the yes; having a hardware brightness/contrast
controls would be a HUGE boon as well).

\- Can we use an US keyboard layout?

~~~
zokier
> Can it be put in a very silent case but still with a fan so as to not
> overheat?

The fan itself probably will heat up more than the chips here.

~~~
arcticbull
It does appear to use a linear regular though, which is always a mixed bag
from a heat generation perspective as a primary power supply.

~~~
linker3000
Murata OKI-78SR-5/1.5-W36-C. These are size and pin compatible with the
classic 7805 linear regulators, but operate at around 90% efficiency and can
supply up to 1.5A without needing a heatsink.

[https://power.murata.com/data/power/oki-78sr.pdf](https://power.murata.com/data/power/oki-78sr.pdf)

[https://github.com/linker3000/Z80-Board/blob/master/z80-6.jp...](https://github.com/linker3000/Z80-Board/blob/master/z80-6.jpg)

~~~
arcticbull
That's so cool, I had no idea these things existed. Thanks for sharing! I
usually just route out my own buck converter.

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posterboy
> ... the 23LCV512 has the interesting property of being able to operate at 5
> volts, so that’s the main reason the microcomputer is called DAN64

I don't understand ...

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detaro
wrong scope/weird sentence structure. 64 since he found a fitting 64k chip
(one running with the right voltage), not 32 as planned I guess.

~~~
reidrac
That's right. Sorry, English is not my first language.

