14 ms·

I feel like there's probably some market for something even smaller than today's FPGAs. I'm picturing situations where you might use a handful of 74xx componen

by hakfoo 4y ago

I feel like there's probably some market for something even smaller than today's FPGAs. I'm picturing situations where you might use a handful of 74xx components to perform a task, but start getting bogged down by factors like "I can't fit 15 chips on my breadboard and even if I did, I'd probably mess up the wiring accidentally". A full "software at runtime" microcontroller solution introduces its own nuances (having to load and initialize, potential timing factors), even if the price is right. A still-in-production commercial-grade FPGA means replacing $10 of parts with $100, so it's not really hobbyist-friendly, and may be wildly overkill for the task. I guess maybe the PAL/GAL ecosystem is sort of what I'm envisioning, but it seems like a dead-end of obscure tools and parts labelled "not suggested for new designs". Or maybe there's a yet-to-be-tapped market for a small-scale hobbyist FPGA that's priced accordingly.

stn8188 4y ago
This is the perfect use case for the Lattice MachXO3 and similar parts. The software doesn't require a licence for the low end parts, and they are cheap and simple to use.
kragen 4y ago
In between the dead PAL/GAL ecosystem and today's FPGAs, you have CPLDs. A 32-macrocell 15-nanosecond ATF1502ASV will run you US$2.42 from Digi-Key https://www.digikey.com/en/products/detail/microchip-technology/ATF1502ASV-15JU44/1008571 https://www.digikey.com/en/products/detail/microchip-technol... and a 64-macrocell 10-nanosecond 3.3-volt M4A3-64 will run you US$6.90 https://www.digikey.com/en/products/detail/lattice-semiconductor-corporation/M4A3-64-32-10VNC48/3457383 https://www.digikey.com/en/products/detail/lattice-semicondu.... You can replace a heck of a lot of 74xx components with a 64-macrocell CPLD, the software tooling for CPLDs is significantly less antiquated than the PAL/GAL tooling, and the designs are as open as the PAL/GAL designs. The thing is, though, if you can stomach a BGA, a 640-LUT iCE40UL640 FPGA is only US$2.80 via Digi-Key https://www.digikey.com/en/products/detail/lattice-semiconductor-corporation/ICE40UL640-SWG16ITR1K/5130904 https://www.digikey.com/en/products/detail/lattice-semicondu..., so it's hard to justify using a CPLD instead in a new design. Maybe easier since the shortage crisis. But that's a "still-in-production commercial-grade† FPGA" and it's US$2.80 in parts, not US$100. A reel of 1000 is US$2340. Is this the small-scale hobbyist FPGA you're looking for? I think you can fit two or three RISC-V controllers on it with SeRV, and it includes 56 kbits (7 KiBytes?) of EBRAM. (Disclaimer: I don't actually know any of this stuff, I'm just repeating things I've read without really understanding them.) ______ † I'm not sure what you mean by "commercial-grade"? I mean it's not a university research project? Lattice is a commercial company and sells the iCE40UL640 as a commercial product.
- gaudat 4y ago
  Commerical grade refers to the temperature range the component is tested to work. Amusingly it is the lowest grade where you can get industrial grade, military grade or even space grade components. I tried to work with those lattice parts once but they were so tiny (0.3 or 0.4mm pitch bga) basically undoable by cheap Chinese hobbyist board houses.
  - kragen 4y ago
    The WLCSP is even tinier pitch! I was thinking maybe I could superglue the chip to a board balls up and dead-bug it? Thanks for the explanation of "commercial-grade" as "not automotive-grade"!
    - r3012 4y ago
      I think the usual technique for soldering a BGA is a lot easier. https://hackaday.com/2021/02/28/bga-soldering-and-inspection/ https://hackaday.com/2021/02/28/bga-soldering-and-inspection... At the bottom of the page you'll see a link to someone who followed your suggestion. Now that looks hard. :)
- hakfoo 4y ago
  "Commercial grade" was a terrible choice of words, I know. I guess I was looking for "currently on offer, and in a phase of lifecycle where you could design a long-lifecycle product around it without a panicked mid-life crisis to replace the chip when supplies ran out." Not "15 year old parts that have deprecated to the point where they're hobbyist-priced". I suppose another big problem with a lot of more sophisticated offerings is, as you suggest, BGA may be hard to stomach. Anything more complex than through-hole packages, or socketable versions is going to dramatically raise the bar for "this can be shipped as a kit and home-assembled." The PLCC one might be viable from that context. Yeah, the "we'll drill your PCB" houses will also tack down your SMD parts, but it changes the proposition. Instead of selling a $10 blank PCB and saying "order what you need from Mouser" you suddenly have a lot more money sunk in partially or fully assembled inventory.
r3012 4y ago
A small GreenPAK is perfect for this. There’s also mixed signal versions just in case you also want an opamp, or two. https://www.renesas.com/tw/en/products/programmable-mixed-signal-asic-ip-products/greenpak-programmable-mixed-signal-products https://www.renesas.com/tw/en/products/programmable-mixed-si...

by hakfoo 4y ago

stn8188 4y ago

This is the perfect use case for the Lattice MachXO3 and similar parts. The software doesn't require a licence for the low end parts, and they are cheap and simple to use.

kragen 4y ago

In between the dead PAL/GAL ecosystem and today's FPGAs, you have CPLDs. A 32-macrocell 15-nanosecond ATF1502ASV will run you US$2.42 from Digi-Key https://www.digikey.com/en/products/detail/microchip-technology/ATF1502ASV-15JU44/1008571 https://www.digikey.com/en/products/detail/microchip-technol... and a 64-macrocell 10-nanosecond 3.3-volt M4A3-64 will run you US$6.90 https://www.digikey.com/en/products/detail/lattice-semiconductor-corporation/M4A3-64-32-10VNC48/3457383 https://www.digikey.com/en/products/detail/lattice-semicondu.... You can replace a heck of a lot of 74xx components with a 64-macrocell CPLD, the software tooling for CPLDs is significantly less antiquated than the PAL/GAL tooling, and the designs are as open as the PAL/GAL designs. The thing is, though, if you can stomach a BGA, a 640-LUT iCE40UL640 FPGA is only US$2.80 via Digi-Key https://www.digikey.com/en/products/detail/lattice-semiconductor-corporation/ICE40UL640-SWG16ITR1K/5130904 https://www.digikey.com/en/products/detail/lattice-semicondu..., so it's hard to justify using a CPLD instead in a new design. Maybe easier since the shortage crisis. But that's a "still-in-production commercial-grade† FPGA" and it's US$2.80 in parts, not US$100. A reel of 1000 is US$2340. Is this the small-scale hobbyist FPGA you're looking for? I think you can fit two or three RISC-V controllers on it with SeRV, and it includes 56 kbits (7 KiBytes?) of EBRAM. (Disclaimer: I don't actually know any of this stuff, I'm just repeating things I've read without really understanding them.) ______ † I'm not sure what you mean by "commercial-grade"? I mean it's not a university research project? Lattice is a commercial company and sells the iCE40UL640 as a commercial product.

gaudat 4y ago
Commerical grade refers to the temperature range the component is tested to work. Amusingly it is the lowest grade where you can get industrial grade, military grade or even space grade components. I tried to work with those lattice parts once but they were so tiny (0.3 or 0.4mm pitch bga) basically undoable by cheap Chinese hobbyist board houses.
- kragen 4y ago
  The WLCSP is even tinier pitch! I was thinking maybe I could superglue the chip to a board balls up and dead-bug it? Thanks for the explanation of "commercial-grade" as "not automotive-grade"!
  - r3012 4y ago
    I think the usual technique for soldering a BGA is a lot easier. https://hackaday.com/2021/02/28/bga-soldering-and-inspection/ https://hackaday.com/2021/02/28/bga-soldering-and-inspection... At the bottom of the page you'll see a link to someone who followed your suggestion. Now that looks hard. :)
hakfoo 4y ago
"Commercial grade" was a terrible choice of words, I know. I guess I was looking for "currently on offer, and in a phase of lifecycle where you could design a long-lifecycle product around it without a panicked mid-life crisis to replace the chip when supplies ran out." Not "15 year old parts that have deprecated to the point where they're hobbyist-priced". I suppose another big problem with a lot of more sophisticated offerings is, as you suggest, BGA may be hard to stomach. Anything more complex than through-hole packages, or socketable versions is going to dramatically raise the bar for "this can be shipped as a kit and home-assembled." The PLCC one might be viable from that context. Yeah, the "we'll drill your PCB" houses will also tack down your SMD parts, but it changes the proposition. Instead of selling a $10 blank PCB and saying "order what you need from Mouser" you suddenly have a lot more money sunk in partially or fully assembled inventory.

r3012 4y ago

A small GreenPAK is perfect for this. There’s also mixed signal versions just in case you also want an opamp, or two. https://www.renesas.com/tw/en/products/programmable-mixed-signal-asic-ip-products/greenpak-programmable-mixed-signal-products https://www.renesas.com/tw/en/products/programmable-mixed-si...