RISCBoy is an open-source portable games console, designed from scratch

Developer Wren6991 has released RISCBoy, an open-source portable games console designed from scratch, according to project documentation. The design includes a RISC-V compatible central processing unit, a raster graphics pipeline, display controller and chip infrastructure such as bus fabric, memory controllers, UART and GPIO. A printed circuit board layout was created in KiCad. The project is described as a Game Boy Advance from a parallel universe where RISC-V existed in 2001. The design is written in synthesizable Verilog 2005 and targets the iCE40-HX8k FPGA, a LUT4-based device with 7,680 logic elements. The processor supports the RV32IMC instruction set and passes the RISC-V compliance suite, the riscv-formal verification suite and additional formal property checks. It also supports M-mode control and status registers, exceptions and a simple compliant extension for vectored external interrupts. The repository uses submodules for hardware description language and tests. The RV32IMC toolchain is required for compilation of software-based tests. On smaller FPGAs such as the iCE40 UP5k, RISCBoy may be configured to use a smaller RV32I variant. FPGA synthesis uses an open-source toolchain including Yosys, nextpnr and Project Icestorm. The Rev A PCB is compatible with iTead's 4-layer 5x5 cm prototyping service at a cost of $65 for 10 boards. Rev B will look different pending gateware and bootloader maturity. Experimental support exists for the ECP5 FPGA.