GoKawiilRISCBoy
RISCBoy is an open-source portable games console, designed from scratch. This includes:
A RISC-V compatible CPU
A raster graphics pipeline and display controller
Other chip infrastructure: busfabric, memory controllers, UART, GPIO etc.
A PCB layout in KiCad
It is a Gameboy Advance from a parallel universe where RISC-V existed in 2001. A love letter to the handheld consoles from my childhood, and a 3AM drunk text to the technology that powered them.
The design is written in synthesisable Verilog 2005, and is intended to fit onto an iCE40-HX8k FPGA. This is a LUT4-based FPGA with 7680 logic elements, so fitting a 32 bit games console requires a crowbar and some vaseline, or perhaps just careful design. The HX8k was once the largest FPGA targeted by the open-source Icestorm FPGA toolchain, but that toolchain has since moved on to greater things.
More detailed information can be found in the documentation.
The processor supports the RV32IMC instruction set, and passes the RISC-V compliance suite for these instructions, as well as the riscv-formal verification suite, and some of my own formal property checks for instruction frontend consistency and basic bus compliance. It also supports M-mode CSRs, exceptions, and a simple compliant extension for vectored external interrupts.
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