Supported DSP System Toolbox Blocks with CMSIS Library for ARM Cortex-M Processors

DSP System Toolbox™ Simulink® blocks that work with Embedded Coder® Support Package for ARM® Cortex®-M Processors support code replacement with the CMSIS library only under specific conditions. You must configure the blocks to enable code replacement when generating C code from a model. The support package does not support multi-rate DSP blocks in the ARM CRL library.

Note

  • In the fixed-point mode of the CMSIS DSP functions (FIR and Biquad filters), Wrap is used for intermediate MAC operations if accumulator result overflows. At the end, the accumulator is right shifted and saturated to the output data type. For discrete FIR and Biquad filter blocks, there is only one overflow setting for accumulator and output. So if overflow happens in accumulation, the simulation result will not match the CMSIS library result. If Overflow Mode is set to 'Wrap' or SaturateOn IntegerOverflow is turned off and only the output overflows, the simulation result will also not match the CMSIS library result.

  • The DSP System Toolbox blocks configured for code replacement using the CMSIS library throw an error when there is an overflow in the SRAM buffer on the PIL or hardware.

The DSP System Toolbox blocks support code replacement using the CMSIS library when you configure the blocks as shown in the following table.

DSP blockSupported data typesInput/Output requirementsParameter requirementsWrapper calling CMSIS functions
Discrete FIR Filter

  • single

  • fixdt(true,32,31)

  • fixdt(true,16,15)

  • fixdt(true,8,7)

Note

The Direct Form structure supports both single and fixed-point data types.

  • Real inputs

  • Real outputs

  • Input and output must be of the same data type.

  • Single or multi channel

  • Input and output coefficients must be of the same data type.

  • Filter structure: Direct Form

  • Input processing: Columns as channels (frame based).

  • Initial states: 0.

  • Coefficients source: Dialog parameters or Input port.

  • For fixed-point inputs, you must enable Saturate on integer overflow. For floating-point inputs, you enable or disable this option.

For fixed-point Discrete FIR Filter block with Direct Form Structure:

  • Rounding mode: 'Floor'.

  • LockScale: On.

  • Q15-specific: Number of filter coefficients must be even and greater than or equal to 4. If not, pad zeros at the end.

'Direct Form' structure:

  • mw_arm_fir_f32

  • mw_arm_fir_init_f32

  • Fixed-point input with Q7 format:

    • mw_arm_fir_q7

    • mw_arm_fir_init_q7

  • Fixed-point input with Q15 format:

    • mw_arm_fir_q15

    • mw_arm_fir_init_q15

  • Fixed-point input with Q31 format:

    • mw_arm_fir_q31

    • mw_arm_fir_init_q31

FIR Decimation (DSP System Toolbox)

  • single

  • Real inputs

  • Real outputs

  • Single or multi channel

  • Input and output coefficients must be of the same data type.

  • Coefficients source: Dialog parameters.

  • Filter structure: Direct Form

  • Input processing: Columns as channels (frame-based).

  • Rate options: Enforce single-rate processing.

  • Allow arbitrary frame length for fixed-size input signals: Clear the parameter.

  • mw_arm_fir_decimate_init_f32

  • mw_arm_fir_decimate_f32

FIR Interpolation (DSP System Toolbox)

  • single

  • Real inputs

  • Real outputs

  • Single or multi channel

  • Input and output coefficients must be of the same data type.

  • Coefficients source: Dialog parameters or Input port.

  • Input processing : Columns as channels (frame based).

  • Rate options: Enforce single-rate processing.

  • mw_arm_fir_interpolate_init_f32

  • mw_arm_fir_interpolate_f32

LMS Filter (DSP System Toolbox)

  • single

  • Real inputs

  • Real outputs

  • Single or multi channel

  • Specify step size via: Dialog (mu specified from the dialog).

  • Reset port:None.

  • Output filter weights : off (no weights output port).

  • Adapt port : off (no adapt output port).

  • Leakage: 1.

  • Initial value of filter weights: 0.

  • Algorithm: LMS or Normalized LMS.

  • arm_lms_init_f32

  • arm_lms_f32

If the algorithm is Normalized LMS:

  • arm_lms_norm_f32

  • arm_lms_norm_init_f32

Biquad Filter (DSP System Toolbox)

  • single

  • fixdt(true,32,31)

  • fixdt(true,16,15)

  • Real inputs

  • Real outputs

  • Input and output must be of the same data type.

  • Single or multi channel

  • Input and output coefficients must be of the same data type.

  • Coefficients source: Dialog parameters or Input port(s).

    • Restriction: If Coefficient source is Input port(s), replacement only occurs when Scale value mode is set to Assume all are unity and optimize.

  • Filter structure: Direct Form I or Direct Form II transposed.

  • Initial conditions: 0.

  • Input processing: Columns as channels (frame based).

  • For fixed-point inputs, you must enable Saturate on integer overflow. For floating-point inputs, you enable or disable this option.

For fixed-point support for Direct Form I Structure for Q15, Q31, and Q15 fast version:

  • Rounding mode: 'Floor'.

  • Overflow mode: Wrap or Saturate.

  • Lock data type settings: On.

Direct Form I structure:

  • mw_arm_biquad_cascade_df1_init_f32

  • mw_arm_biquad_cascade_df1_f32

  • mw_arm_biquad_cascade_df1_init_q15

  • mw_arm_biquad_cascade_df1_q15

  • mw_arm_biquad_cascade_df1_fast_q15

  • mw_arm_biquad_cascade_df1_init_q31

  • mw_arm_biquad_cascade_df1_q31

Direct Form II transposed structure:

  • mw_arm_biquad_cascade_df2T_init_f32

  • mw_arm_biquad_cascade_df2T_f32

FFT (DSP System Toolbox)

  • single

  • Complex values

  • Single or multi channel

  • Input length must be equal to FFT length.

  • FFT implementation: Radix-2.

  • Scale result by FFT length: Off (check box is cleared).

  • Inherit FFT length from input dimensions: Off (check box is cleared).

  • FFT length: 16, 64, 256, 1024

  • mw_arm_cfft_init_f32

  • mw_arm_cfft_f32

IFFT (DSP System Toolbox)

  • single

  • Complex values

  • Single or multi channel

  • Input length must be equal to FFT length.

  • FFT implementation: Radix-2.

  • Divide output by FFT length: On (check box is selected).

  • Inherit FFT length from input dimensions: Off (check box is cleared).

  • FFT length: 16, 64, 256, 1024

  • mw_arm_cfft_init_f32

  • mw_arm_cfft_f32

Correlation (DSP System Toolbox)
Convolution (DSP System Toolbox)

  • single

  • Real inputs

  • Real outputs

  • Single channel

  • The two inputs must be of the same length.

  • Computation domain: Time.

  • arm_conv_f32

  • arm_correlate_f32

Mean (DSP System Toolbox)
RMS (DSP System Toolbox)
Variance (DSP System Toolbox)
Standard Deviation (DSP System Toolbox)

  • single

  • Non-scalar real inputs

  • Real outputs

  • Single channel (one dimensional)

  • The two inputs must be the same length.

  • Running statistic

    : Off (check box is cleared).

  • Enable ROI Processing: Off (check box is cleared). ROI does not apply to RMS.

  • Find statistic over: entire input.

  • arm_mean_f32

  • arm_rms_f32

  • arm_var_f32

  • arm_std_f32

Second-Order Section Filter (DSP System Toolbox)

  • single

  • Real inputs

  • Real outputs

  • Input and output must be of the same data type.

  • Input and output coefficients must be of the same data type.

  • Coefficients source: Dialog parameters or Input port(s).

    • Restriction: If Coefficient source is Input port(s), replacement occurs only when Scale value mode is set to Assume all are unity and optimize.

  • Filter structure: Direct Form I.

  • Input processing: Columns as channels (frame based).

'Direct Form I' structure:

  • mw_arm_biquad_cascade_df1_init_f32

  • mw_arm_biquad_cascade_df1_f32

See Also