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Pequeno (PQR5) is a 5-stage pipelined in-order RISC-V CPU Core compliant with RV32I ISA.

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iammituraj/pequeno_riscv

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pequeno_riscv

Pequeno (meaning "tiny" in Spanish) aka PQR5 is a 5-staged pipelined in-order RISC-V CPU Core compliant with RV32I ISA.

Overview

  • RV32I ISA v2.2 + custom instructions

    Assembler and Instruction Manual: https://github.com/iammituraj/pqr5asm)

    FPGA demo of Pequeno running Hello world program: https://youtu.be/GECyL9U5ZxI

  • Single-core, Single-issue, In-order execution

  • Classic 5-stage RISC-V pipeline

  • Intended for baremetal applications, not OS & interrupt capable.

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                                          / CHIPMUNK LOGIC            /\
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                                       /     / P e q u e n o  /   / \/
                                      /     /  RISC-V 32I    /    /\
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      chipmunklogic.com                                                    [[[[[[[ O P E N - S O U R C E _
    

Feature set

CPU Feature Set
ISA RV32I, user-level v2.2
Instructions All 37 base instructions + 16 custom instructions
Cores 1
Issue One instruction per cycle
Pipeline depth 5
Fetch, Decode, Execution, Memory Access, Writeback
Bus architecture Harvard, separate instruction/data bus
Branch Prediction Yes, static
Cache Not available, but can be integrated externally
OS capable No, privilege modes are not supported
Interrupt/Exceptions capable No
Debug support Yes, limited number of signals for simulation purposes only

Important notes

Please go through database_readme.txt for information about the organisation of the repo and how to setup the pqr5 build environment.

Disclaimer

This CPU core is intended for educational purposes only. Users are encouraged to review the accompanying license document (LICENSE) for detailed terms and conditions.

Developer

Mitu Raj, Chipmunk Logic, [email protected]