4 ms·
There's a community doing "fpga golf". That is, reducing the number of LUT required to implement a CPU of a given ISA. A basic RV32 CPU is down to 500-700 LUT.
by jpfr 4y ago
There's a community doing "fpga golf".
That is, reducing the number of LUT required to implement a CPU of a given ISA.
A basic RV32 CPU is down to 500-700 LUT.
https://github.com/YosysHQ/picorv32
https://github.com/olofk/serv
A minimal 8051 requires about 300 LUT.
https://github.com/MicroCoreLabs/Projects/tree/master/MCL51
Not sure how this translates from an FPGA to a transistor count. But RV32 and 8051 should be within a factor of 2-3.
- Taniwha 4y agoIf all you're doing is making a core with a little ROM, a USB interface and a flash interface chances are your design is pad limited - it probably doesn't matter which CPU you use provided it's tinyish (oh and 8051 are a pain to work with, they've taken far too much of my lifetime, they need the stake thru the heart thing)
- snvzz 4y ago>If all you're doing is making a core with a little ROM, a USB interface and a flash interface An interesting observation is that RV32 has excellent code density. Meaning, in this sort of scenario, the ROM could be much smaller, or fit way more code at the same size.
- userbinator 4y agowithin a factor of 2-3 That's still a huge difference, and as I mentioned above, the 8051 is found in applications which are very sensitive to cost. In terms of gate count, the lowest numbers I could find for a RISC-V core are in the 10-20k range, while an 8051 goes down to 2.7k: https://www.electronicsweekly.com/news/design/eda-and-ip/8051-core-squeezed-into-2700-gates-2009-03/ https://www.electronicsweekly.com/news/design/eda-and-ip/805...