arm_pid_init_q31.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        19. March 2015
00005 * $Revision:    V.1.4.5
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_pid_init_q31.c    
00009 *    
00010 * Description:  Q31 PID Control initialization function     
00011 *    
00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE.  
00039 * ------------------------------------------------------------------- */
00040 
00041 #include "arm_math.h"
00042 
00043  /**    
00044  * @addtogroup PID    
00045  * @{    
00046  */
00047 
00048 /**    
00049  * @brief  Initialization function for the Q31 PID Control.   
00050  * @param[in,out] *S points to an instance of the Q31 PID structure.   
00051  * @param[in]     resetStateFlag  flag to reset the state. 0 = no change in state 1 = reset the state.   
00052  * @return none.    
00053  * \par Description:   
00054  * \par    
00055  * The <code>resetStateFlag</code> specifies whether to set state to zero or not. \n   
00056  * The function computes the structure fields: <code>A0</code>, <code>A1</code> <code>A2</code>    
00057  * using the proportional gain( \c Kp), integral gain( \c Ki) and derivative gain( \c Kd)    
00058  * also sets the state variables to all zeros.    
00059  */
00060 
00061 void arm_pid_init_q31(
00062   arm_pid_instance_q31 * S,
00063   int32_t resetStateFlag)
00064 {
00065 
00066 #ifndef ARM_MATH_CM0_FAMILY
00067 
00068   /* Run the below code for Cortex-M4 and Cortex-M3 */
00069 
00070   /* Derived coefficient A0 */
00071   S->A0 = __QADD(__QADD(S->Kp, S->Ki), S->Kd);
00072 
00073   /* Derived coefficient A1 */
00074   S->A1 = -__QADD(__QADD(S->Kd, S->Kd), S->Kp);
00075 
00076 
00077 #else
00078 
00079   /* Run the below code for Cortex-M0 */
00080 
00081   q31_t temp;
00082 
00083   /* Derived coefficient A0 */
00084   temp = clip_q63_to_q31((q63_t) S->Kp + S->Ki);
00085   S->A0 = clip_q63_to_q31((q63_t) temp + S->Kd);
00086 
00087   /* Derived coefficient A1 */
00088   temp = clip_q63_to_q31((q63_t) S->Kd + S->Kd);
00089   S->A1 = -clip_q63_to_q31((q63_t) temp + S->Kp);
00090 
00091 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
00092 
00093   /* Derived coefficient A2 */
00094   S->A2 = S->Kd;
00095 
00096   /* Check whether state needs reset or not */
00097   if(resetStateFlag)
00098   {
00099     /* Clear the state buffer.  The size will be always 3 samples */
00100     memset(S->state, 0, 3u * sizeof(q31_t));
00101   }
00102 
00103 }
00104 
00105 /**    
00106  * @} end of PID group    
00107  */