|
|
/*-----------------------------------------------------------------------------
|
|
|
* Copyright (C) 2010 ARM Limited. All rights reserved.
|
|
|
*
|
|
|
* $Date: 15. July 2011
|
|
|
* $Revision: V1.0.10
|
|
|
*
|
|
|
* Project: CMSIS DSP Library
|
|
|
* Title: arm_fir_decimate_init_f32.c
|
|
|
*
|
|
|
* Description: Floating-point FIR Decimator initialization function.
|
|
|
*
|
|
|
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
|
|
|
*
|
|
|
* Version 1.0.10 2011/7/15
|
|
|
* Big Endian support added and Merged M0 and M3/M4 Source code.
|
|
|
*
|
|
|
* Version 1.0.3 2010/11/29
|
|
|
* Re-organized the CMSIS folders and updated documentation.
|
|
|
*
|
|
|
* Version 1.0.2 2010/11/11
|
|
|
* Documentation updated.
|
|
|
*
|
|
|
* Version 1.0.1 2010/10/05
|
|
|
* Production release and review comments incorporated.
|
|
|
*
|
|
|
* Version 1.0.0 2010/09/20
|
|
|
* Production release and review comments incorporated
|
|
|
*
|
|
|
* Version 0.0.7 2010/06/10
|
|
|
* Misra-C changes done
|
|
|
* ---------------------------------------------------------------------------*/
|
|
|
|
|
|
#include "arm_math.h"
|
|
|
|
|
|
/**
|
|
|
* @ingroup groupFilters
|
|
|
*/
|
|
|
|
|
|
/**
|
|
|
* @addtogroup FIR_decimate
|
|
|
* @{
|
|
|
*/
|
|
|
|
|
|
/**
|
|
|
* @brief Initialization function for the floating-point FIR decimator.
|
|
|
* @param[in,out] *S points to an instance of the floating-point FIR decimator structure.
|
|
|
* @param[in] numTaps number of coefficients in the filter.
|
|
|
* @param[in] M decimation factor.
|
|
|
* @param[in] *pCoeffs points to the filter coefficients.
|
|
|
* @param[in] *pState points to the state buffer.
|
|
|
* @param[in] blockSize number of input samples to process per call.
|
|
|
* @return The function returns ARM_MATH_SUCCESS if initialization was successful or ARM_MATH_LENGTH_ERROR if
|
|
|
* <code>blockSize</code> is not a multiple of <code>M</code>.
|
|
|
*
|
|
|
* <b>Description:</b>
|
|
|
* \par
|
|
|
* <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
|
|
|
* <pre>
|
|
|
* {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
|
|
|
* </pre>
|
|
|
* \par
|
|
|
* <code>pState</code> points to the array of state variables.
|
|
|
* <code>pState</code> is of length <code>numTaps+blockSize-1</code> words where <code>blockSize</code> is the number of input samples passed to <code>arm_fir_decimate_f32()</code>.
|
|
|
* <code>M</code> is the decimation factor.
|
|
|
*/
|
|
|
|
|
|
arm_status arm_fir_decimate_init_f32(
|
|
|
arm_fir_decimate_instance_f32 * S,
|
|
|
uint16_t numTaps,
|
|
|
uint8_t M,
|
|
|
float32_t * pCoeffs,
|
|
|
float32_t * pState,
|
|
|
uint32_t blockSize)
|
|
|
{
|
|
|
arm_status status;
|
|
|
|
|
|
/* The size of the input block must be a multiple of the decimation factor */
|
|
|
if((blockSize % M) != 0u)
|
|
|
{
|
|
|
/* Set status as ARM_MATH_LENGTH_ERROR */
|
|
|
status = ARM_MATH_LENGTH_ERROR;
|
|
|
}
|
|
|
else
|
|
|
{
|
|
|
/* Assign filter taps */
|
|
|
S->numTaps = numTaps;
|
|
|
|
|
|
/* Assign coefficient pointer */
|
|
|
S->pCoeffs = pCoeffs;
|
|
|
|
|
|
/* Clear state buffer and size is always (blockSize + numTaps - 1) */
|
|
|
memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(float32_t));
|
|
|
|
|
|
/* Assign state pointer */
|
|
|
S->pState = pState;
|
|
|
|
|
|
/* Assign Decimation Factor */
|
|
|
S->M = M;
|
|
|
|
|
|
status = ARM_MATH_SUCCESS;
|
|
|
}
|
|
|
|
|
|
return (status);
|
|
|
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* @} end of FIR_decimate group
|
|
|
*/
|
|
|
|
