Baby-Risco-5 Processor Core

Introduction

Risco-5 is a 32-bit RISC-V core that implements the basic instruction set of the RISC-V RV32I/E[M]. Risco-5 is a multi-cycle, in-order processor without a pipeline. It was designed to be simple and easy to use, making it useful in various systems.

Source Files

The Risco-5 files are available in the "core/" folder within the "src/" directory, with the top module located in the core.v file.

Parameters

Name	Size	Description
BOOT_ADDRESS	32 bits	Boot address

Signals

Name	Direction	Size	Description
clk	input	1 bit	Clock signal
halt	input	1 bit	Halts the processor execution
reset	input	1 bit	Reset signal
memory_response	input	1 bit	Memory bus response; the core waits until it is 1
memory_read	output	1 bit	Enables memory read
memory_write	output	1 bit	Enables memory write
write_data	output	32 bits	Values exiting the core
read_data	input	32 bits	Values coming from memory
address	output	32 bits	Memory address
option	output	3 bits	Format to be read from memory

Instance Example

Below is an example of how to instantiate the Risco-5 core in a Verilog module:

Core #(
    .BOOT_ADDRESS(32'h00000000) // Boot address - 32 bits
) Core_inst (
    /* control */
    .clk(clk), // Clock signal - 1 bit
    .halt(halt), // Halts the processor execution - 1 bit
    .reset(reset), // Reset signal - 1 bit
    /* Data */
    .memory_response(memory_response), // Memory bus response, the core waits until it is 1 - 1 bit
    .memory_read(memory_read), // Enables memory read - 1 bit
    .memory_write(memory_write), // Enables memory write - 1 bit
    .write_data(write_data), // Values exiting the core - 32 bits
    .read_data(read_data), // Values coming from memory - 32 bits
    .address(address), // Memory address - 32 bits
    .option(option) // Format to be read from memory - 3 bits
);

Control Unit State Machine and Schematic

Control Unit State Machine

Processor Schematic

Current Schematic

Initial Schematic