1. There must be a GCC or LLVM compiler available
2. No vendor specific CPU, a CPU should run on all FPGA’s
If possible, a simple ready to go SoC with Uart, Timer and GPIO is nice, but no requirement.
And the following FPGAs made the cut:
I liked the Vexriscv, LEON3 and NEO430 the most in terms of usability. None of them were perfect. Vexriscv is very flexible, but lacks documentation in some areas, LEON3 probably works perfect with a commercial license and the NEO430 lacks a debugger. But all in all, those three seem the best choices in my opinion if you need a CPU for an FPGA project.
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