GRV3000D - Digital Signal Controller


The PulseRain GRV3000D is a fixed-point digital signal controller. It features a RISC-V dual-issue in-order processor core, plus a versatile digital signal co-processor. The highlights of the GRV3000D are as following:

  •  6-stage pipeline that can issue and execute up to two instructions in one clock cycle

  • 24-bit address bus and 64-bit data bus 

  • A true Harvard architecture with completely separate data memory and instruction memory

  • AXI4-Lite switch for peripherals

  • Support two 32-bit MAC operation in one clock cycle

  • Built-in DSP coprocessor (CP)

  • JTAG port for Debugging

Instruction Set
​The GRV3000D supports the following RISC-V instruction sets (ISA):

  • RISC-V RV32I Base Integer Instruction Set, Version 2.1

  • RISC-V “Zifencei”, Instruction-Fetch Fence, Version 2.0

  • RISC-V “M” Standard Extension for Integer Multiplication and Division, Version 2.0

  • (Optional) RISC-V "C" Standard Extension for Compressed Instructions, Version 2.0

  • RISC-V “Zicsr”, Control and Status Register (CSR) Instructions, Version 2.0

  • RISC-V Base Counters and Timers

DSP Coprocessor


Unlike other RISC-V DSP solutions, the DSP Coprocessor (CP) in GRV3000D triggers the DSP acceleration through RISC-V HINT, without using any additional private instructions. In this way, the DSP acceleration is non-intrusive and it does not rely on any specific compilers to function. And the DSP CP currently supports the following operations:

  • Normalization for samples in block

  • Absolute value for samples in block

  • Negative value for samples in block

  • Value clipping for samples in block

  • Left logic shift for samples in block

  • Right logic shift, right arithmetic shift and right arithmetic shift with rounding for samples in block

  • FIR filter for samples in block, with a throughput of two samples per clock cycle

  • BIQUAD cascade filter for samples in block, with a throughput of three clock cycles per BIQUAD

  • Dot Product (Real and Complex)

  • FFT (Fast Fourier Transform

And the DSP Coprocessor from GRV3000D can offer unrivaled performance. Here is a FFT performance matrix for the GRV3000D against ARM Cortex-M:

Software Library

To further facilitate the adoption of the GRV3000D in DSP applications, an open-source software library called PMSIS (PulseRain Microcontroller Software Interface Standard) is also provided to the general public for free. And this library can be found in GitHub at