[petra]

Here's this experiment sort-of running:

WCH, which sells cheap mcu's(like $0.25 8051-mcu with usb/16Kflash) is working on a risc-V bluetooth mcu:

https://www.cnx-software.com/2019/02/16/wch-ch572-risc-v-mcu...

And since risc-v has versions somewhere around 5K-10K gates, well, a lower end mcu isn't far, probably.

Still, it would be interesting to think how we can get from that, to standard peripherals, and standard pinouts, used by at least 2 mcu makers. That would be interesting.

[vardump]

> And since risc-v has versions somewhere around 5K-10K gates, well, a lower end mcu isn't far, probably.

5-10k? Seriously? That's amazing.

Z80 had 8500. According to Wikipedia, even truly simple and bare bones 6502 had 3510 or 3218.

[tasty_freeze]

The Z80 had that many transistors, not gates

The CMOS rule of thumb is one gate is 4 transistors (eg a 2-input NAND). But the first Z80 was nmos, and so the equivalent count is harder to state. 3 transistors per 2 input nmos gate is a rough first order guess, but in nmos wide gates still need only a single load resistor, and designers sometimes used dynamic logic to save even more transistors.

[vardump]

Ohh... This is embarrassing! I work in embedded/low level and I have always thought that gate == transistor. It's really obvious in retrospect...

I stand corrected.

[marshray]

It's not a crazy idea, there are indeed logic types that implement some gate types with a single transistor. For example, https://en.wikipedia.org/wiki/Resistor–transistor_logic

These were more commonly used back when transistors were expensive.

[kragen]

Designs like the GreenArrays F18A core show that you can do dramatically more than the 6502 or Z80 did in a similar number of transistors. The J1 and J1A are free descendants. The MOStek and Zilog hackers were wizards but they were working under serious time and, in the Zilog case, compatibility constraints. We know enough to do better now.

(https://news.ycombinator.com/item?id=20688443 is on the same topic.)

(As others commented, those are transistor counts.)

[petra]

Smallest irsc-v core i know: https://devhub.io/repos/kammoh-picorv32

~1000 Luts. 1 Lut = 6-24 gates on average. a bit pmore but still pretty close.

[vardump]

A LUT can be 10 gates and it can be 100+ gates. You just can't compare FPGA LUTs to gates like that.

FPGAs have things like block RAMs and multipliers. Those require a ton of gates, but don't increase required FPGA LUT count by much.