Welcome to the CORE-V-MCU User Manual!
The purpose of the CORE-V-MCU is to showcase the CV32E40P (v1.0.0), the first member of the OpenHW Group’s CORE-V family of RISC-V cores. The CORE-V-MCU also supports an embedded FPGA (eFPGA) provided by Quicklogic. The eFPGA is a memory mapped resource for the CV32E40P core and may also be connected to the MCU’s user I/O pins. In addition, the CORE-V-MCU supports 512KB of on-chip SRAM and a rich set of I/O peripherals:
2 QSPI masters
2 I2C masters
1 CPI (Camera)
1 GPIO unit with 32 I/O
1 I2C slave
1 Advanced Timer (PWM) with 4 channels
In addition to the above, a small set of support peripherals is available to the processor core:
Clock and Reset Generator
The UARTs, I2C masters, QSPI, SDIO and Camera periphals transfer data to and from on-chip memory via a micro-DMA unit. With the exception of the eFPGA, all of the above are open source artifacts, permissively licensed under Soldpad 2.1.
Copyright 2022, 2023 OpenHW Group.
Copyright 2018 ETH Zurich and University of Bologna.
Copyright and related rights are licensed under the Solderpad Hardware License, Version 2.1 or newer (the “License”); you may not use CORE-V-MCU source files except in compliance with the License. You may obtain a copy of the License at http://solderpad.org/licenses. Unless required by applicable law or agreed to in writing, software, hardware and materials distributed under this License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
An Open Source Project¶
We encourage people to get involved and contribute to this project. Please have a look at the Open Source Development at the OpenHW Group chapter of this User Manual.
The CORE-V-MCU processor core is the CV32E40P v1.0.0, a standards-compliant 32-bit RISC-V processor. It follows these specifications:
RISC-V Instruction Set Manual, Volume I: User-Level ISA, Document Version 20191213 (December 13, 2019)
RISC-V Instruction Set Manual, Volume II: Privileged Architecture, document version 20190608-Base-Ratified (June 8, 2019). CV32E40P implements the Machine ISA version 1.11.
RISC-V External Debug Support, draft version 0.13.2 (https://github.com/riscv/riscv-debug-spec/tree/4e0bb0fc2d843473db2356623792c6b7603b94d4)
In addition to the above, the CORE-V-MCU supports peripherals that adhere to one or more of the following standards:
UART: defacto standard - please see the UDMA UART chapter of this User Manual for more information.
QSPI: defacto standard - please see the UDMA QSPI Master chapter of this User Manual for more information.
I2C: UM10204 - I2C-bus specification and user manual. Rev. 6 — 4 April 2014. NXP Semiconductors
SDIO: specification for the Secure Digital IO are maintained by the SD Association (https://www.sdcard.org)
CPI: Camera Parallel Interface
JTAG: 1149.7-2009 - IEEE Standard for Reduced-Pin and Enhanced-Functionality Test Access Port and Boundary-Scan Architecture
Who Should Read This Document¶
The principle audience of this document are users of the CORE-V-MCU ASIC or FPGA implementations, primarily verification and/or software engineers. Although some aspects of the RTL implementation are discussed, this document is not a description of the micro-architecture of the CORE-V-MCU, nor does it describe in detail the structure of the RTL.
The source repository for this document is https://github.com/openhwgroup/core-v-mcu.git. This repository contains the RTL model of the CORE-V-MCU, a simple simulation testbench, plus a set of Makefiles, FuseSoC core files and scripts to generate several physical implementations:
OpenHW ASIC implemented in GF-22FDX.
Digilent Nexys A7 with the Xilinx Artix-7 XC7A100T FPGA.
Digilent Genesys 2 with the Xilinx Kintex-7 XC7K325T FPGA.
The open source nature of this project enables the user to port the CORE-V-MCU to almost any implementation technology and to alter is configuration.
In fact, the repository is organizated to simplify the task of customizing an implementation.
For example, a set of macros (tick defines) in
rtl/includes/pulp_soc_defines.svh defines which micro-DRAM peripherals (and how many) are incorporated in the build.
Generate statements in the RTL are in place to instanitate the correct peripheral set as per pulp_soc_defines.svh, and a python script at
util/ioscript.py should extract some useful documentation and configuration data to be used during simulation and synthesis.
Please note that these capabilties have not been extensively tested and only the peripheral set and physical implementations defined above are known to build properly.