nuclei-sdk/SoC/evalsoc

NMSIS Core Device Templates

The evalsoc implementation in Nuclei SDK serves as a latest reference implementation of the NMSIS Core Device Templates.

Device templates located in https://github.com/Nuclei-Software/NMSIS/tree/master/Device/_Template_Vendor will not be updated anymore.

We support the following toolchains in this evalsoc implementation:

• Nuclei RISC-V GNU Toolchain: https://doc.nucleisys.com/nuclei_tools/toolchain/gnu/index.html
• Nuclei RISC-V LLVM Toolchain: https://doc.nucleisys.com/nuclei_tools/toolchain/llvm/index.html
• IAR RISC-V Toolchain: http://iar.com/riscv
• Terapines ZCC Toolchain: https://www.terapines.com/products/zcc

Quick Porting Guide

To quickly port this SDK to your custom SoC (designed with Nuclei 200/300/600/900/1000 series CPU), please refer to our comprehensive porting guide:

Porting Guide: From EvalSoC to Custom SoC

Directory Structure

Board Support (Board/nuclei_fpga_eval/)

• Configuration Files

  • npk.yml: Board Support Package Configuration File for NPK
  • openocd_evalsoc.cfg: OpenOCD configuration for on-board debugging using HummingBird Debugger
  • openocd_xlspike.cfg: Nuclei internal use only. OpenOCD configuration for xlspike simulation, not for general use

• Header Files (Include/)

  • nuclei_sdk_hal.h: Hardware abstraction layer interface
  • Defines debug UART (UART0)
  • Configures debug output or suppress debug output via NMSIS_DISABLE_DEBUG
  • board_nuclei_fpga_eval.h: Board specific header file for peripheral access if needed

• Linker Scripts (Source/GCC/ and Source/IAR/)

  • Source/GCC: Linker Scripts for GCC/Clang toolchain
  • Source/IAR: Linker Scripts for IAR toolchain
  • Support for multiple download modes in GCC/Clang toolchain:
  • gcc_evalsoc_ilm.ld: code placed in ilm, data placed in dlm
  • gcc_evalsoc_flash.ld: code and data in flash, but code will be copied to ilm, data will be copied to dlm when running
  • gcc_evalsoc_flashxip.ld: code and data in flash, but code will still in flash, data will be copied to dlm when running
  • gcc_evalsoc_ddr.ld: code and data all placed in ddr
  • gcc_evalsoc_sram.ld: code and data all placed in sram
  • Support for multiple run modes in IAR toolchain:
  • flash download mode is not supported

SoC Support (Common/)

Core Definition Files

• evalsoc.svd: System View Description file, provided by SoC vendor

  • Peripheral register definitions
  • Interrupt configurations
  • Memory map details

• npk.yml: SoC Support Package Configuration File for NPK

Include Files (Common/Include/)

• cpufeature.h: Nuclei RISC-V CPU feature header file

  • This file is generated by nuclei_gen tool
  • Used by evalsoc.h to define CPU feature macros used in NMSIS Core header files

• evalsoc.h: Core SoC definitions

  • Base addresses for peripherals
  • Interrupt definitions
  • Nuclei RISC-V CPU feature macros
  • You can customize this file to add more SoC definitions

• evalsoc_uart.h: UART driver interface

• system_evalsoc.h: System configuration

  • Clock initialization
  • Core initialization routines
  • System frequency setup
  • Interrupt(ECLIC/PLIC/CLINT) and Exception API

• nuclei_sdk_soc.h: SDK SoC common header file

  • Includes all peripheral headers
  • Common definitions for the SoC
  • Include evalsoc.h

Source Files (Common/Source/)

• Startup/Interrupt and Exception Code

  • Startup Code:
  • GCC/Clang version: GCC/startup_evalsoc.S
  • IAR version: IAR/startup.S and IAR/startup_evalsoc.c
  • Interrupt and Exception Code:
  • GCC/Clang version: M-Mode -> GCC/intexc_evalsoc.S, S-Mode -> GCC/intexc_evalsoc_s.S
  • IAR version: M-Mode -> IAR/intexc_evalsoc.S, S-Mode -> IAR/intexc_evalsoc_s.S

• System Configuration Code

  • evalsoc_common.c: get soc frequency via timer freq, and delay function and etc, which can be deleted if not needed
  • system_evalsoc.c: template code for system configuration, it will do premain initialization, smp bringup, cache initialization, interrupt and exception initialization, uart initialization and print banner, you can customize it as needed

• Driver Implementations(Drivers)

  • UART driver: evalsoc_uart.c

• Standard C Library Stub Code(Stubs)

  • Newlib stubs: Stubs/newlib
  • IAR DLib stubs: Stubs/iardlib
  • Nuclei C Runtime Library(libncrt) stubs: Stubs/libncrt
  • You only need one of them depending on your which c library you are using

Build Configuration

• build.mk: Main build rules for the SoC

  • CPU ARCH related compiler flags such as march, mabi and mtune
  • Include paths
  • Source files
  • Support code if you have qemu or other simulators supported

• cpufeature.mk: CPU extension configuration

  • Select which CPU Core you are using, see https://doc.nucleisys.com/nuclei_sdk/develop/buildsystem.html#develop-buildsystem-var-core
  • Select which CPU extensions you are using, see https://doc.nucleisys.com/nuclei_sdk/develop/buildsystem.html#arch-ext
  • Used by build.mk

• runmode.mk: Nuclei internal use only.

  • Make variables to control ilm/dlm/icache/dcache on/off mode
  • Make variables to control Nuclei CPU features such as eclic/plic/tee/smpu/cidu present or not
  • WARNING: This is not recommended for general use, it is only for Nuclei internal use