#include "ref.h"
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float32_t ref_pid_f32(
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arm_pid_instance_f32 * S,
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float32_t in)
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{
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float32_t out;
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/* y[n] = y[n-1] + A0 * x[n] + A1 * x[n-1] + A2 * x[n-2] */
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out = S->state[2] + S->A0 * in + S->A1 * S->state[0] + S->A2 * S->state[1];
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/* Update state */
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S->state[1] = S->state[0];
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S->state[0] = in;
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S->state[2] = out;
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/* return to application */
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return (out);
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}
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q31_t ref_pid_q31(
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arm_pid_instance_q31 * S,
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q31_t in)
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{
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q63_t acc;
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q31_t out;
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/* acc = A0 * x[n] */
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acc = (q63_t) S->A0 * in;
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/* acc += A1 * x[n-1] */
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acc += (q63_t) S->A1 * S->state[0];
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/* acc += A2 * x[n-2] */
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acc += (q63_t) S->A2 * S->state[1];
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/* convert output to 1.31 format to add y[n-1] */
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out = (q31_t) (acc >> 31U);
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/* out += y[n-1] */
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out += S->state[2];
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/* Update state */
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S->state[1] = S->state[0];
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S->state[0] = in;
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S->state[2] = out;
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/* return to application */
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return (out);
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}
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q15_t ref_pid_q15(
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arm_pid_instance_q15 * S,
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q15_t in)
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{
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q63_t acc;
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q15_t out;
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q15_t A1, A2;
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#if defined (ARM_MATH_DSP)
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#ifndef ARM_MATH_BIG_ENDIAN
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A2 = S->A1 >> 16;
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A1 = (q15_t)S->A1;
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#else
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A1 = S->A1 >> 16;
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A2 = (q15_t)S->A1;
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#endif
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#else
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A1 = S->A1;
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A2 = S->A2;
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#endif
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/* acc = A0 * x[n] */
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acc = ((q31_t) S->A0) * in;
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/* acc += A1 * x[n-1] + A2 * x[n-2] */
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acc += (q31_t) A1 * S->state[0];
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acc += (q31_t) A2 * S->state[1];
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/* acc += y[n-1] */
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acc += (q31_t) S->state[2] << 15;
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/* saturate the output */
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out = ref_sat_q15(acc >> 15);
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/* Update state */
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S->state[1] = S->state[0];
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S->state[0] = in;
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S->state[2] = out;
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/* return to application */
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return (out);
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}
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