The signal processing library contains various primitive DSP functions such as FIR, IIR and FFT. There are different libraries offered on a variety of Renesas CPU families, tool chain and OS configurations. These functions are fine-tuned and optimized for various architectures.

This product provides the basic signal processing library (SPL) functions necessary for building signal processing applications using High-performance Embedded Workshop (HEW) that uses "C/C++ Compiler Package for SuperH Family" (SHC compiler) or any other appropriate environments (Eg: QNX, Wince etc). (See the conceptual image shown below.)

Release Information

Software Ver.: V.2.00.00

Application Note Ver.: V.1.00.00

Released: Apr 09, 2010

The signal processing library (SPL) is used in wafer positioning equipment, automobile application, Acoustic Echo Canceller (AEC), speech processing, Knock sensing, image processing and other applications. Speedy development as well as cost reduction of such devices can be achieved via a combination of Renesas microcontrollers, Renesas middleware, and Renesas development tools (compilers, debuggers, etc.).

SPL evaluation sample code is also available. For details, please refer to "Application Notes and Sample code".

SP Libraries are available in different configuration on different targets. They are as shown in the below block diagram.

  • FFF - Input - Float, SPL Internal computation - Float, Output - Float
  • IFI - Input - Integer, SPL Internal computation - Float, Output - Integer
  • III - Input - Integer, SPL Internal computation - Integer, Output - Integer
  • The target blocks with solid line are completed or under development phase. But the blocks with dotted lines are to be done (TBD) and will be added in future.



  • SP library implements some of the most frequently used functions in typical Signal processing application such as speech processing, Knock sensing, image processing, etc...
  • Sample software code to demonstrate the use of the library functions
  • Performance analysis on SH2A-FPU, SH4A-FPU, RX600 and R32C Platform.
  • Efficient development through a combined use of Renesas development tools supported
  • Functions supported
    1. Filters
      • FIR filter
      • IIR Biquad filter
    2. Transforms
      • FFT (Fast Fourier Transform)
        • a. Real FFT (Forward / Inverse)
        • b.Complex FFT (Forward / Inverse)
    3. Multi-rate filtering
      • Decimation using cascaded FIR filters
    4. Vector operations
      • Dot product
      • Sum of absolutes


Function name Description
rta_cfft1d Complex Fast Fourier transform supports both forward and inverse
rta_rfft1d Real Fast Fourier transform supports both forward and inverse
rta_initfft Initializes the Real and Complex FFT functions.
rta_dsplib_decim4_fir FIR Filter with Decimation by factor of 4.
rta_dsplib_decim8_boxcar Boxcar Filter with Decimation by factor of 8
rta_dsplib_decim8_fir FIR Filter with Decimation by factor of 8.
rta_dsplib_decim_fir FIR Filter with Generic Decimation by any factor.
rta_dsplib_decim_process Cascaded Decimation Filter Chain
rta_dsplib_decim_process_init Initialize the list of concatenated Decimation FIR Filters.
rta_vecops_fdotprod Vector dot-product.
rta_dsplib_fir 1-Dimensional FIR filtering function.
rta_vecops_fsumabs Vector Summation.
rta_dsplib_iirBiquad IIR Biquad Filter.
rta_dsplib_get_version Get the version of SP library.


  • Signal Processing functions in library (binary form)
  • Signal Processing sample software made by High-performance Embedded Workshop (HEW) 1
  • Signal Processing Application program Interface (API) User manual
  • SP Library Installation instructions and performance analysis document.
  • The User manual and document are also available in *.chm Microsoft compiled HTML help file format.

1.The sample workspaces are verified on the evaluation boards placed in the Supported Evaluation boards page.

Modular Composition

The modular composition will provide information on different layers that are involved in running the evaluation sample code.

Application Examples

Example of application field

  • Knock sensing device controls and monitors the Rotation per minute (RPM) of the power train system in automobiles
  • The IIR Biquad filter function present in the Signal Processing Library (SPL) is used for this application
  • The feedback provided from Knock tool is used to control the speed Rotation per minute (RPM) of the power train system

Conceptual image of knock sensing device for Automobile constructed

The real time data from power train system is captured through knock sensor. The sensor captured data is provided as input to Signal processing library running on Renesas MCU. IIR Biquad function present inside the Signal Processing Library (SPL) is used for filtering in this particular application. Filtered data is provided to knock tool which analyses and provides a feedback to power train system to control the speed Rotation per minute (RPM).

Operating Environment

Target Devices SH2A-FPU, SH4A, RX600, R32C
Applicable compiler SH2A-FPU, SH4A C/C++ Compiler Package for SuperH Family V.9.03.00
RX600 C/C++ Compiler Package for RX Family V.
R32C C Compiler Package for R32C Series V.1.02 Release 00
ROM (SH2A-FPU) SP Library Approx. 8.87KB
RAM (SH2A-FPU) SP Library (stack usage) Approx. 0.5KB
SP Library (I/O Buffers) Approx. 4.88KB

Actual I/O buffer usage depends on Input parameters (Filter length, FFT Length etc).


Supported Evaluation Boards

The evaluation boards listed below are available that help you start using Signal processing Library.

The sample code developed on High-performance Embedded Workshop (HEW) can be used directly to run on one of the board.

Target MCU Evaluation board
SH2A-FPU SH7216 Renesas Starter Kit+ for SH7216
SH7264 Renesas Starter Kit+ for SH7264
RX600 RX62N Renesas Starter Kit+ for RX62N



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