10 ms·

The Forth Deck mini: a portable Forth computer with a discrete CPU

295 points by hggh 2y ago

simlevesque 2y ago
woah, four lines display ? that's luxury. I remember coding on a single line display, kids these days...
- rbanffy 2y ago
  My Epson HX-20 has 4 lines but only 20 characters each.
artemonster 2y ago
I have used to have an obsession with Forth and discrete CPUs when I was a teenager (if you google hard enough you will find an ancient webring of homebuilt CPUs out of discrete components), this obsession led me to my profession now - Digital Hardware Designer. My heart fills with joy when I see such posts at top of HN :) Great work!
pushfoo 2y ago
TL;DR: Looks like a step toward the AlphaSmart of programming If you don't remember the AlphaSmart[1], it was a line of typewriter-like devices with small LCD displays. They ran on batteries for hours and had limited save space. You could hook them up to a larger computer to save your drafts. Where's the programming version of that? The recent HN post[2] about running a Mac 128k on a RPI2040[3] got me thinking about that. In theory, you could get real work done on a system like that, although it wouldn't be very good for entertainment. So, where's the AlphaSmart of low-power computing? 1. "Real" keyboard 2. Low-power display, ideally a larger e-ink one 3. Not connected to the internet To be clear, I don't mean a TI-83-like[4], TI-92[5], or even the recent NumWorks[6]. Those are meant to be calculators and have inconvenient calculator-like form-factors. [1]: https://en.wikipedia.org/wiki/AlphaSmart https://en.wikipedia.org/wiki/AlphaSmart [2]: https://news.ycombinator.com/item?id=40699684 https://news.ycombinator.com/item?id=40699684 [3]: https://axio.ms/projects/2024/06/16/MicroMac.html https://axio.ms/projects/2024/06/16/MicroMac.html [4]: https://en.wikipedia.org/wiki/TI-83_series https://en.wikipedia.org/wiki/TI-83_series [5]: https://en.wikipedia.org/wiki/TI-92_series https://en.wikipedia.org/wiki/TI-92_series [6]: https://www.numworks.com/ https://www.numworks.com/
- voltaireodactyl 2y ago
  Even just an e ink alphasmart would be killer — the key feature for me was the Mac keyboard + shortcuts so I never had to think while using it.
  - pushfoo 2y ago
    TL;DR: Freewrite[1] tries but it isn't the same They are selling a line of professionally oriented devices. I'm not sure they're worth it. * The "Alpha" model[2] nods to the AlphaSmart form factor, but it isn't e-ink * Weird-looking keyboard layouts with no Apple-style key in sight * These devices are expensive for what they seem to offer I've never used one so I can't really speak about more than what I've seen on the site. There were some negative reviews of earlier models. I'm not sure how current ones rate, nor what their keyboard feels like. [1]: https://getfreewrite.com/ https://getfreewrite.com/ [2]: https://getfreewrite.com/products/alpha https://getfreewrite.com/products/alpha
- kragen 2y ago
  i've been wanting that for years myself, and with the advent of sharp's memory-in-pixel lcd displays and ambiq's subthreshold-logic arm microcontrollers, it's become possible to make it work under a milliwatt, which means it can run purely on solar power without batteries, using parallel nand flash for mass storage at a low duty cycle. i haven't progressed beyond the earliest prototyping stage myself; my design notes on the so-called zorzpad (mostly in spanish) are in http://canonical.org/~kragen/sw/zorzpad.git/ http://canonical.org/~kragen/sw/zorzpad.git/ and za3k vance has been working on a project inspired by it called the zorchpad https://blog.za3k.com/tag/zorchpad/ https://blog.za3k.com/tag/zorchpad/ the primary objective of the zorzpad is longevity, with a design lifetime of 53 years. to reach that objective i think i can't use batteries, charging ports, or off-the-shelf keyswitches. this forces a lot of compromises on the system design; i haven't found a processor with an mmu that can run at under a milliwatt ("zorzpad" is a pun on "thinkpad"; it's pronounced "thorthpad" in some spanish dialects, so it's the opposite of a thinkpad) i think e-ink displays probably use way too much power. for years i've been looking for solid power consumption numbers, but in their absence, dividing an amazon swindle's battery life by its battery capacity suggests that they use about 100 milliwatts. the zorzpad's e-ink displays are about a tenth as big, use about a thousandth as much power (100 microwatts), and can be updated at 60 hertz (though the datasheet only guarantees 20) if you aren't worried about going batteryless, or about mass production, you could literally buy an alphasmart neo and wire its keyboard and display up to an esp32 or something
ForHackernews 2y ago
Hmmm... http://collapseos.org/forth.html http://collapseos.org/forth.html
xlii 2y ago
There’s implementation of Forth for Cardputter[0] if anyone is interested. I tried to boot it and it worked. I’m not a Forth enthusiast myself but was thinking about doing something with Uiua, as I think it’s really fun toy language for such application. [0]: https://github.com/ryu10/M5CardForth https://github.com/ryu10/M5CardForth
- andypiper 2y ago
  Oh, interesting. Would that be installable OTA using M5Launcher?
mongol 2y ago
Reminds me about Oric-1 https://en.m.wikipedia.org/w/index.php?title=Oric_(computer)&diffonly=true https://en.m.wikipedia.org/w/index.php?title=Oric_(computer)...
mjg59 2y ago
Some prior art in terms of computers with built-in Forth interpreters: https://en.wikipedia.org/wiki/Jupiter_Ace https://en.wikipedia.org/wiki/Jupiter_Ace And, of course, the Open Firmware used on Suns, PowerPC Macs, the One Laptop per Child, and others made use of Forth (including for the ROMs in expansion cards, allowing them to be CPU-agnostic): https://en.wikipedia.org/wiki/Open_Firmware https://en.wikipedia.org/wiki/Open_Firmware
phire 2y ago
I love reading about optimised Discrete CPUs like this. Only 16 logic ICs. Doesn't even have an adder, the only ALU function is a 1 bit Nor gate. Details on this page: http://mynor.org/my4th.htm http://mynor.org/my4th.htm
- bananaboy 2y ago
  This is fantastic!
fallat 2y ago
I've built 5 of the author's My4th Light boards. Contact me (bio) if you're interested in one. I wouldn't mind building a batch of Forth Deck minis if people are interested too. I plan to do a small demo video on Forth but haven't gotten around to it yet.
spiritplumber 2y ago
The Parallax Propeller 2 comes with this by default, check it out.
anigbrowl 2y ago
If you are into tiny computers but not especially moved by Forth or the prospect of soldering, you can get a rather capable ESP32 box for $30: https://shop.m5stack.com/products/m5stack-cardputer-kit-w-m5stamps3 https://shop.m5stack.com/products/m5stack-cardputer-kit-w-m5...
- bottom999mottob 2y ago
  Wow... everything from M5Stack looks capable for the price. $30 for the capabilities of the Flipper Zero is nice.
  - anigbrowl 2y ago
    Yes, though note you'd need to add a few modules to get the full capabilities of the FZ (eg the RFID reading and 432Hz antennas iirc). Be warned that the documentation is kinda minimal, so if you're new to IOT stuff there's quite a learning curve. There are fairly decent core libraries in C and also a fairly capable micropython stock, but you have to be willing to figure out a lot of stuff on your own or with the help of their user forums.
  - notatoad 2y ago
    every time somebody posts the M5stack site, i just want to order everything. but on some level, i know it'll all end up on the pile of projects that i've started and not yet finished.
- xattt 2y ago
  “Backorder”
  - anigbrowl 2y ago
    It appears as available for me. As a fairly regular buyer from them (but not in commercial quantities or anything close) my experience is that their restocking turnarounds are usually only a few weeks. They're very responsive via email if you want to inquire ahead.
- 2y ago
electrodank 2y ago
What is this exactly? What do you do with it?
- fallat 2y ago
  You program anything your heart desires :) * it can be a calculator * it can be a text editor * it can be a side scrolling shooter * it can be a text adventure * it can be a life simulator * it can be an algorithm playground * it can be a way to work on larger programs in smaller pieces in quiter places! etc.
whartung 2y ago
What's the modern day barrier to creating a "hobby" TRS-80 Model 100? 40x8 LCD display, one of the best keyboards ever made. I see the custom keyboard community seem to be able to make any keyboard they like. The keyboard on the Model 100 consumed the majority of its space, but at the same time, it was usable. I don't know what a reasonable display would be. The notable thing about the 40x8 is that it was big enough to be usable, and it was readable. I've seen some decks with tiny 640x480 displays, and they're not readable, particularly to my aging eyes. The Psion 5 had a very usable keyboard, and better display than the M100. I don't know if that kind of keyboard can be made by a hobbyist like the other ones can. I don't know enough about keyboards. I don't know if one of those could be gutted and repurposed. (No doubt considered sacrilege to some.) We see these "decks" with these matrices of buttons, but I'd dare say they're not really keyboards. The PET 2001 kind of proved that (and I did a lot of coding on a PET back in the day). So, just curious what's stopping "real" ones, "nice" ones from showing up. I'd dare say money, but I see what folks spend money on for their hobbies, so it can't be that alone. Doesn't have to be a viable product for market.
- Gracana 2y ago
  Finding big low resolution displays is a pain. Pixel density has increased a lot, so larger displays are high resolution, which means you need a much faster device to drive them, and at that point it starts to feel a little silly because your display controller is way more powerful than the actual computer. That's the stumbling block I've run into, anyway. It's plenty doable, it just feels sillier than I intend.
- bongodongobob 2y ago
  Why would you? Back then, keyboards weren't peripherals. Now they are. Restricting peoples choice doesn't make sense. Get whatever keyboard you want. What's stopping you from using whatever keyboard you want? Nothing, at that's what progress looks like. Buy whatever keyboard you want.
  - robxorb 2y ago
    Substitute "keyboard" for "computer" for most of your comment to see how it misses the point.
tailrecursion 2y ago
The CPU for this computer is microcoded and is made out of a small number of discrete logic chips, plus an EEPROM. The data and address bus are 8 bits wide but the NOR unit operates on one bit only. The microcode has to loop in order to perform an 8 bit add. I was looking for a hardware shifter in the diagram, because I figured it'd be necessary to access bits D1-D7. But there is none. He uses a lookup table in EEPROM to do the shift. If you're interested in nice CPU designs, here's another one: the Novix NC4000 (also RTX2000), in which the bits in the instructions lead directly to control various muxes and units inside the chip. There's almost no decoding.
abdellah123 2y ago
how much does this cost?
Pet_Ant 2y ago
What I'd love is a dialect of Factor written in Forth so that it could be run on these machines. Factor is a much higher-level Forth that is usable for scripting. Would make it more fun to use.
eschneider 2y ago
Oh, this is _nice_! It's not quite what I'd want, but all the schematics and software is there, so it wouldn't be too hard to change things to taste. :)

295 points by hggh 2y ago

simlevesque 2y ago

woah, four lines display ? that's luxury. I remember coding on a single line display, kids these days...

rbanffy 2y ago
My Epson HX-20 has 4 lines but only 20 characters each.

artemonster 2y ago

I have used to have an obsession with Forth and discrete CPUs when I was a teenager (if you google hard enough you will find an ancient webring of homebuilt CPUs out of discrete components), this obsession led me to my profession now - Digital Hardware Designer. My heart fills with joy when I see such posts at top of HN :) Great work!

pushfoo 2y ago

TL;DR: Looks like a step toward the AlphaSmart of programming If you don't remember the AlphaSmart[1], it was a line of typewriter-like devices with small LCD displays. They ran on batteries for hours and had limited save space. You could hook them up to a larger computer to save your drafts. Where's the programming version of that? The recent HN post[2] about running a Mac 128k on a RPI2040[3] got me thinking about that. In theory, you could get real work done on a system like that, although it wouldn't be very good for entertainment. So, where's the AlphaSmart of low-power computing? 1. "Real" keyboard 2. Low-power display, ideally a larger e-ink one 3. Not connected to the internet To be clear, I don't mean a TI-83-like[4], TI-92[5], or even the recent NumWorks[6]. Those are meant to be calculators and have inconvenient calculator-like form-factors. [1]: https://en.wikipedia.org/wiki/AlphaSmart https://en.wikipedia.org/wiki/AlphaSmart [2]: https://news.ycombinator.com/item?id=40699684 https://news.ycombinator.com/item?id=40699684 [3]: https://axio.ms/projects/2024/06/16/MicroMac.html https://axio.ms/projects/2024/06/16/MicroMac.html [4]: https://en.wikipedia.org/wiki/TI-83_series https://en.wikipedia.org/wiki/TI-83_series [5]: https://en.wikipedia.org/wiki/TI-92_series https://en.wikipedia.org/wiki/TI-92_series [6]: https://www.numworks.com/ https://www.numworks.com/

voltaireodactyl 2y ago
Even just an e ink alphasmart would be killer — the key feature for me was the Mac keyboard + shortcuts so I never had to think while using it.
- pushfoo 2y ago
  TL;DR: Freewrite[1] tries but it isn't the same They are selling a line of professionally oriented devices. I'm not sure they're worth it. * The "Alpha" model[2] nods to the AlphaSmart form factor, but it isn't e-ink * Weird-looking keyboard layouts with no Apple-style key in sight * These devices are expensive for what they seem to offer I've never used one so I can't really speak about more than what I've seen on the site. There were some negative reviews of earlier models. I'm not sure how current ones rate, nor what their keyboard feels like. [1]: https://getfreewrite.com/ https://getfreewrite.com/ [2]: https://getfreewrite.com/products/alpha https://getfreewrite.com/products/alpha
kragen 2y ago
i've been wanting that for years myself, and with the advent of sharp's memory-in-pixel lcd displays and ambiq's subthreshold-logic arm microcontrollers, it's become possible to make it work under a milliwatt, which means it can run purely on solar power without batteries, using parallel nand flash for mass storage at a low duty cycle. i haven't progressed beyond the earliest prototyping stage myself; my design notes on the so-called zorzpad (mostly in spanish) are in http://canonical.org/~kragen/sw/zorzpad.git/ http://canonical.org/~kragen/sw/zorzpad.git/ and za3k vance has been working on a project inspired by it called the zorchpad https://blog.za3k.com/tag/zorchpad/ https://blog.za3k.com/tag/zorchpad/ the primary objective of the zorzpad is longevity, with a design lifetime of 53 years. to reach that objective i think i can't use batteries, charging ports, or off-the-shelf keyswitches. this forces a lot of compromises on the system design; i haven't found a processor with an mmu that can run at under a milliwatt ("zorzpad" is a pun on "thinkpad"; it's pronounced "thorthpad" in some spanish dialects, so it's the opposite of a thinkpad) i think e-ink displays probably use way too much power. for years i've been looking for solid power consumption numbers, but in their absence, dividing an amazon swindle's battery life by its battery capacity suggests that they use about 100 milliwatts. the zorzpad's e-ink displays are about a tenth as big, use about a thousandth as much power (100 microwatts), and can be updated at 60 hertz (though the datasheet only guarantees 20) if you aren't worried about going batteryless, or about mass production, you could literally buy an alphasmart neo and wire its keyboard and display up to an esp32 or something

ForHackernews 2y ago

Hmmm... http://collapseos.org/forth.html http://collapseos.org/forth.html

xlii 2y ago

There’s implementation of Forth for Cardputter[0] if anyone is interested. I tried to boot it and it worked. I’m not a Forth enthusiast myself but was thinking about doing something with Uiua, as I think it’s really fun toy language for such application. [0]: https://github.com/ryu10/M5CardForth https://github.com/ryu10/M5CardForth

andypiper 2y ago
Oh, interesting. Would that be installable OTA using M5Launcher?

mongol 2y ago

Reminds me about Oric-1 https://en.m.wikipedia.org/w/index.php?title=Oric_(computer)&diffonly=true https://en.m.wikipedia.org/w/index.php?title=Oric_(computer)...

mjg59 2y ago

Some prior art in terms of computers with built-in Forth interpreters: https://en.wikipedia.org/wiki/Jupiter_Ace https://en.wikipedia.org/wiki/Jupiter_Ace And, of course, the Open Firmware used on Suns, PowerPC Macs, the One Laptop per Child, and others made use of Forth (including for the ROMs in expansion cards, allowing them to be CPU-agnostic): https://en.wikipedia.org/wiki/Open_Firmware https://en.wikipedia.org/wiki/Open_Firmware

phire 2y ago

I love reading about optimised Discrete CPUs like this. Only 16 logic ICs. Doesn't even have an adder, the only ALU function is a 1 bit Nor gate. Details on this page: http://mynor.org/my4th.htm http://mynor.org/my4th.htm

bananaboy 2y ago
This is fantastic!

fallat 2y ago

I've built 5 of the author's My4th Light boards. Contact me (bio) if you're interested in one. I wouldn't mind building a batch of Forth Deck minis if people are interested too. I plan to do a small demo video on Forth but haven't gotten around to it yet.

spiritplumber 2y ago

The Parallax Propeller 2 comes with this by default, check it out.

anigbrowl 2y ago

If you are into tiny computers but not especially moved by Forth or the prospect of soldering, you can get a rather capable ESP32 box for $30: https://shop.m5stack.com/products/m5stack-cardputer-kit-w-m5stamps3 https://shop.m5stack.com/products/m5stack-cardputer-kit-w-m5...

bottom999mottob 2y ago
Wow... everything from M5Stack looks capable for the price. $30 for the capabilities of the Flipper Zero is nice.
- anigbrowl 2y ago
  Yes, though note you'd need to add a few modules to get the full capabilities of the FZ (eg the RFID reading and 432Hz antennas iirc). Be warned that the documentation is kinda minimal, so if you're new to IOT stuff there's quite a learning curve. There are fairly decent core libraries in C and also a fairly capable micropython stock, but you have to be willing to figure out a lot of stuff on your own or with the help of their user forums.
- notatoad 2y ago
  every time somebody posts the M5stack site, i just want to order everything. but on some level, i know it'll all end up on the pile of projects that i've started and not yet finished.
xattt 2y ago
“Backorder”
- anigbrowl 2y ago
  It appears as available for me. As a fairly regular buyer from them (but not in commercial quantities or anything close) my experience is that their restocking turnarounds are usually only a few weeks. They're very responsive via email if you want to inquire ahead.
2y ago

electrodank 2y ago

What is this exactly? What do you do with it?

fallat 2y ago
You program anything your heart desires :) * it can be a calculator * it can be a text editor * it can be a side scrolling shooter * it can be a text adventure * it can be a life simulator * it can be an algorithm playground * it can be a way to work on larger programs in smaller pieces in quiter places! etc.

whartung 2y ago

What's the modern day barrier to creating a "hobby" TRS-80 Model 100? 40x8 LCD display, one of the best keyboards ever made. I see the custom keyboard community seem to be able to make any keyboard they like. The keyboard on the Model 100 consumed the majority of its space, but at the same time, it was usable. I don't know what a reasonable display would be. The notable thing about the 40x8 is that it was big enough to be usable, and it was readable. I've seen some decks with tiny 640x480 displays, and they're not readable, particularly to my aging eyes. The Psion 5 had a very usable keyboard, and better display than the M100. I don't know if that kind of keyboard can be made by a hobbyist like the other ones can. I don't know enough about keyboards. I don't know if one of those could be gutted and repurposed. (No doubt considered sacrilege to some.) We see these "decks" with these matrices of buttons, but I'd dare say they're not really keyboards. The PET 2001 kind of proved that (and I did a lot of coding on a PET back in the day). So, just curious what's stopping "real" ones, "nice" ones from showing up. I'd dare say money, but I see what folks spend money on for their hobbies, so it can't be that alone. Doesn't have to be a viable product for market.

Gracana 2y ago
Finding big low resolution displays is a pain. Pixel density has increased a lot, so larger displays are high resolution, which means you need a much faster device to drive them, and at that point it starts to feel a little silly because your display controller is way more powerful than the actual computer. That's the stumbling block I've run into, anyway. It's plenty doable, it just feels sillier than I intend.
bongodongobob 2y ago
Why would you? Back then, keyboards weren't peripherals. Now they are. Restricting peoples choice doesn't make sense. Get whatever keyboard you want. What's stopping you from using whatever keyboard you want? Nothing, at that's what progress looks like. Buy whatever keyboard you want.
- robxorb 2y ago
  Substitute "keyboard" for "computer" for most of your comment to see how it misses the point.

tailrecursion 2y ago

The CPU for this computer is microcoded and is made out of a small number of discrete logic chips, plus an EEPROM. The data and address bus are 8 bits wide but the NOR unit operates on one bit only. The microcode has to loop in order to perform an 8 bit add. I was looking for a hardware shifter in the diagram, because I figured it'd be necessary to access bits D1-D7. But there is none. He uses a lookup table in EEPROM to do the shift. If you're interested in nice CPU designs, here's another one: the Novix NC4000 (also RTX2000), in which the bits in the instructions lead directly to control various muxes and units inside the chip. There's almost no decoding.

abdellah123 2y ago

how much does this cost?

Pet_Ant 2y ago

What I'd love is a dialect of Factor written in Forth so that it could be run on these machines. Factor is a much higher-level Forth that is usable for scripting. Would make it more fun to use.

eschneider 2y ago

Oh, this is _nice_! It's not quite what I'd want, but all the schematics and software is there, so it wouldn't be too hard to change things to taste. :)