HN Reader

> So, which pins could be combined with SDIO's three? After much thinking, the solution is obvious. RAM's nCS can be the SD card's CLK. RAM's CLK can be the SD card's CMD. RAM's MOSI can be the SD card's DAT. Try and figure out all the possible interactions with each device and what that would look like to the other, to convince yourself that it will work safely.

This is truly a brilliant hack, well worth publishing at Hacker News.

I have the perverse urge to forego even the board, and just make this a circuit sculpture.

I'm always a bit saddened to see that a separate chip is the go-to method to interface with USB. Unfortunately USB is an incredibly-complex protocol that it seems anything beyond a basic V-USB running USB 1.1 at low-speed is generally not doable without specialized hardware and a significant software stack. Meanwhile a protocol like SPI is ridiculously simple...the minimum hardware needed is a shift register that can be clocked fast enough. I miss how desktop and labtops used to have an exposed serial and parallel port, which could communicate at this low level. I often wonder if instead of USB existing that we instead stuck with UART, I2C, or SPI multidrop (using a small set of standard clock rates) for simple peripherals (maybe over a single connector like the 4-pin JST SH cable for Stemma QT, Qwiic and Grove) over a short distance, and then jumped to IEEE 802.3 Ethernet links for data-heavy peripherals like monitors and external drives. Then instead of having to have separate support for USB and Ethernet, you just would support Ethernet links.

Please tell me you didn't use ENIG for the USB connector. It would be sacrilege.

Aside from the project itself being very cool, this page is a great source for information about small microcontrollers, even if it does omit the WLCSP ones. And it links to the MIPS emulator page for ARM at https://dmitry.gr/?r=05.Projects&proj=33.%20LinuxCard which seems very interesting.

I think it would be cute to also use 8 pin SPI flash chip instead of SD card for storage.

It is interesting how to go to the limits of low-end author needs to implement CPU emulator. It is not obvious, that you need ADD layers at this level, not REMOVE them!

It's almost 2 chips. One is just a USB-serial IC! But you didn't count the SD card, so you're up to 3 again.

Total pin count is so low on this, I'm very tempted to make a dead bug version.

I've dabbled in microcontrollers and enjoy how the limitations force me to find creative solutions, but this is truly next level. I'm not great with a soldering iron but I'm seriously considering assembling one of these.

Thanks, this was very insightful and entertaining once again!

One thing: you might want to mention the required board thickness (0.8mm, iirc?) for people planning to have their own boards made.

Edit, explanation for others: that is required to make the "USB-C edge connector" fit the plug.

It is very cool project, buy I think author (I know, you will read this) take it to the extreme. Again, it is very cool technically, but it contradicts declared goal: to make new computer kit for beginners.

IMHO, it is doesn't matter for novice, what to solder, SOIC8 or SOIC28. SOIC28 is as easy (or hard, if you want) as SOIC8.

And larger chip could make much more useful computer: it will be possible to add some minimal sound (as such chips typically have DAC), keyboard, and, maybe later, true monitor output in VGA style (not DP or HDMI of course).

It will be not much harder (if at all) to solder, but could be good base for expansion if owner gain interest in such things.

This pleasantly reminds me of the little 6502 or 1802 Altoids-tin computers you can buy and assemble, but arguably more "useful" (though I get a lot of use out of a 6502 ;-).

Was there no native ARM linux you could have used? As I recall, you have used this emulated MIPs technique in many of your published projects, so it's good to prove that the hardware is working?

Or why not just go full native....grab some MIPS-core IP and make your own with an FPGA?

I knew it was gonna be dimitry from reading the title

> but I am allergic to RISC-V for personal reasons.

Do you mind elaborating?

> It does not help that modern operating systems require gigabytes of RAM, terabytes of storage, and always-on internet connectivity to properly spy on you

Love it.

Excellent article, thanks. At the risk of missing the forest for the trees, I wonder how much simpler things would have been if you had been slightly flexible on the 8-pin requirement. It seems as though having just a few more pins would have reduced the complexity of the project significantly while only marginally increasing the time it takes to solder.

> There was a time when one could order a kit and assemble a computer at home

I think I get what OP means but you can definitely order a pc kit and just assemble it nowadays

super fun read thanks. cool result too :)! also love all the different options for hw discussed in lot of details. thx!

Why am I imagining this being used for really serverless iot infrastructure?

Like imagine that you wanted to deploy something on a lot of huge devices, well by using something like this open source and really limited but (with it just works), you can actually have pcb providers build it and ship it in their warehouse / wherever and just provide it energy and ethernet and now you can probably ssh into it / even create some sort of Vercel-like UI on top of it(Coolify/Dokploy? though we would need to slim down docker a lot for Dokploy? )

and when the work is done , they would actually scrape the metal /pcb and / reuse it again...

I am not sure if such metal /pcb recycling makes sense...

If anyone technical can respond to this, it would be great.

This can also be done with risc-v as well. I am not sure but I was thinking of creating a very dead simple company (my brain and its weird thoughts... , also Don't copy me or if you do, then hire me xD) which just can take a device like old phones and then just root them using AI? / manual or maybe not even root it? IDK...,

Basically then providing them internet access and energy (Not a traditional warehouse) because you actually only pay for the one time fees and afterwards all the fees that you pay, they are of the real costs bore by the company operating it / no middle man profits.

Kind of like a "Costco" (oh I had forgotten name of Costco and I had to search target alternatives xD) where they actually are there to help you save money but for you to use their services you gotta have a card.

Under parts selection.. Even considering the PIC 16F. Why.