March 3, 2023

EBAZ4205 - Z80 on the Zynq

I got to wondering. I know there are all kinds of FPGA projects that get various 8 bit microprocessors running at crazy clock speeds. I wondered if anyone had done such a thing on a Zynq based unit.

A likely thing seemed to be searching for "Zedboard Z80" or other popular processors along with Zedboard. Sure enough, I turned things up right away.

They say that Multicomp can run a Z80, 6809, or a Z80. Multicomp is/was done by Grant Searle.

68000 on an FPGA

The Nexys is not Zynq based. The Nexys board has an Artix-7 FPGA (which has only 15,800 logic slices, but can run internal clocks up to 450 Mhz). The block ram is 4,860 Kbits (600K bytes). The board also has 128M of DDR ram.

The Xilinx 68k core looks like a commercial offering, as does the DCD core.

Other zedboard projects on Github

Just searching "zedboard github" turns up all kinds of things. The Parallella has a Zynq XC7C010 and claims 18 cores. Two of them are the ARM cores in the Zynq that we already know and love. The other 16 are RISC-V cores running on a E16G301 chip (the Epiphany 16-Core microprocessor). The board has 1G of SDRAM and 1G ethernet. I was excited about this when I thought that the 16 RISC-V cores were running in the Zynq FPGA fabric, but this is not the case.

The board is available in several versions. One is still for sale on Digikey for $149.

RISC-V "Rocketship"

Searching "github zedboard riscv turns up the "Rocket Ship":

Conclusions

All of this would be work studying. Most of this is done in VHDL.

A great project would be getting the 68000 to run on a Zynq (probably the Ebaz). Actually it would be good also to get it running on the Zedboard (and if it runs on the Ebaz it should be easy to get it to run on the Zedboard. The Zedboard would have more popular appeal.

Feedback? Questions? Drop me a line!

Tom's Computer Info / [email protected]