The xr16 RISC processor is designed,now it’s time to design the rest of the System-on-a-Chip (SoC). Besides the CPU, the FPGA hosts an on-chip bus, bus controller, parallel port, RAM,video controller, and an external SRAM controller. This month, I’ll show how simple interfaces can make SoC design as straightforward as classic CPU, glue logic, memory, peripherals, and PCB design used to be.