Diff: cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_init_f32.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_init_f32.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,107 @@
+/*-----------------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_biquad_cascade_df1_init_f32.c    
+*    
+* Description:  floating-point Biquad cascade DirectFormI(DF1) filter initialization function.    
+*    
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*  
+* Version 1.1.0 2012/02/15 
+*    Updated with more optimizations, bug fixes and minor API changes.  
+*   
+* 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 0.0.5  2010/04/26     
+*      incorporated review comments and updated with latest CMSIS layer    
+*    
+* Version 0.0.3  2010/03/10     
+*    Initial version    
+* ---------------------------------------------------------------------------*/
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupFilters    
+ */
+
+/**    
+ * @addtogroup BiquadCascadeDF1    
+ * @{    
+ */
+
+/**    
+ * @details    
+ * @brief  Initialization function for the floating-point Biquad cascade filter.    
+ * @param[in,out] *S           points to an instance of the floating-point Biquad cascade structure.    
+ * @param[in]     numStages    number of 2nd order stages in the filter.    
+ * @param[in]     *pCoeffs     points to the filter coefficients array.    
+ * @param[in]     *pState      points to the state array.    
+ * @return        none    
+ *    
+ *    
+ * <b>Coefficient and State Ordering:</b>    
+ *    
+ * \par    
+ * The coefficients are stored in the array <code>pCoeffs</code> in the following order:    
+ * <pre>    
+ *     {b10, b11, b12, a11, a12, b20, b21, b22, a21, a22, ...}    
+ * </pre>    
+ *    
+ * \par    
+ * where <code>b1x</code> and <code>a1x</code> are the coefficients for the first stage,    
+ * <code>b2x</code> and <code>a2x</code> are the coefficients for the second stage,    
+ * and so on.  The <code>pCoeffs</code> array contains a total of <code>5*numStages</code> values.    
+ *    
+ * \par    
+ * The <code>pState</code> is a pointer to state array.    
+ * Each Biquad stage has 4 state variables <code>x[n-1], x[n-2], y[n-1],</code> and <code>y[n-2]</code>.    
+ * The state variables are arranged in the <code>pState</code> array as:    
+ * <pre>    
+ *     {x[n-1], x[n-2], y[n-1], y[n-2]}    
+ * </pre>    
+ * The 4 state variables for stage 1 are first, then the 4 state variables for stage 2, and so on.    
+ * The state array has a total length of <code>4*numStages</code> values.    
+ * The state variables are updated after each block of data is processed; the coefficients are untouched.    
+ *    
+ */
+
+void arm_biquad_cascade_df1_init_f32(
+  arm_biquad_casd_df1_inst_f32 * S,
+  uint8_t numStages,
+  float32_t * pCoeffs,
+  float32_t * pState)
+{
+  /* Assign filter stages */
+  S->numStages = numStages;
+
+  /* Assign coefficient pointer */
+  S->pCoeffs = pCoeffs;
+
+  /* Clear state buffer and size is always 4 * numStages */
+  memset(pState, 0, (4u * (uint32_t) numStages) * sizeof(float32_t));
+
+  /* Assign state pointer */
+  S->pState = pState;
+}
+
+/**    
+ * @} end of BiquadCascadeDF1 group    
+ */