Arm’s Digital Signal Controllers, Cortex-M4, Cortex-M33 and Cortex-M7, address the need for high-performance generic code processing, as well as digital signal processing applications.
The addition of DSP extensions to the Thumb instruction set, as defined in Arm’s architecture Armv7-M, Armv8-M and the optional floating-point unit (FPU), are designed to improve the performance of numerical algorithms. In addition, they provide the opportunity to perform signal processing operations directly on the Cortex-M4/M33/M7, while maintaining the ease of use of the Cortex-M programmer’s model.
Wide range of DSP and SIMD instructions
The Cortex-M4/M33/M7 provide SIMD instructions that operate on 8-or 16-bit integers. All registers are still 32-bits wide, but the SIMD instructions operate on 2 x 16-bit values or 4 x 8-bit values at a time within a 32-bit register.
One 32-bit word can hold 2x16-bit values or 4x8-bit values
Instructions that work on 8- or 16-bit data types are useful for processing data such as video or audio, as they do not require full 32-bit precision. The SIMD instructions allow these 2x16-bit or4x8-bit operations to be performed in parallel.
The CMSIS-DSP library is a suite of common signal processing and mathematical functions that have been optimized for Cortex-M4, Cortex-M7 and Cortex-M33 processors. The library is freely available as part of the CMSIS release from Arm and includes all source code.
The functions in the library are divided into several categories:
- Basic math functions, such as Vector Dot Product, Vector Multiply, Vector Addition
- Fast math functions, such as Square Root, Sine and Cosine
- Complex math functions, such as Complex Dot Product, Complex-by-real Multiplication
- Filters, such as FIR, IIR, Biquad and Convolution
- Matrix functions, such as Matrix Multiplication, Complex Matrix Multiplication
- Transforms, such as Complex FFT functions
- Motor control functions, including Vector Clarke Transform, Vector Park Transform, PID Motor Control
- Statistical functions, including Root Mean Square (RMS), Standard deviation, Maximum and Power
- Support functions, e.g. conversion of datatypes from float to fixed point
- Interpolation functions.
The CMSIS-DSP library has separate functions for operating on 8-bit integers, 16-bit integers, 32-bit integers, and 32-bit floating point values.
Strong ecosystem for DSP applications
A wide range of DSP software packages for Cortex-M4, Cortex-M7 and Cortex-M33 is available.
Learn more about Arm's DSP ecosystem partners who offer these software packages below:
Video and speech codecs:
Audio enhancement algorithms:
|MP3 Decoder||G.711||Echo cancellation|
|MP3 Encoder||G722||Noise suppression|
|MPEG-2 Layer 2 Decoder||G.722.1||Beamforming|
|MPEG-2 Layer 2 encoder||G.722.2||Voice Activity Detection|
|AAC-LC decoder||G.723.1||Key Word Spotting|
|AAC-LD decoder||G.728||Wind noise reduction|
|AAC-ELC encoder||G.729||Automatic Gain Control|
|SBC bluetooth decoder||AMR Narrowband|
|SBC Bluetooth encoder||AMR Wideband|
|Ogg Vorbis||AMR Wideband+|
For more help and information, see these resources:
DSP capabilities of Cortex-M4 and Cortex-M7
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