An Alternative to x21

[Dave Lowry <lowry@xxxxxxxxxxxxxxxxx>]

Those who do not subscribe to Dr. Ting's Forth Engines
newsletter may not know that he has reverse-engineered
MuP21.  He has written, in Verilog and VHDL, a 16 bit
"clone".  At present, it's just the CPU, no video.

I have synthesized the VHDL version, and run it in a
Xilinx gate array at about 25 MHz.  This is not too
terribly far from the real-world performance of the x21
chips running out of DRAM.  Plus, the chip seems to
perform much more reliably than MuP21.

-Dave

(all opinions mine, not those of my employer, etc.)