65 lines
1.6 KiB
C
65 lines
1.6 KiB
C
/* Reflow Oven Controller
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*
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* Copyright (C) 2021 Mario Hüttel <mario.huettel@gmx.net>
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*
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* This file is part of the Reflow Oven Controller Project.
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*
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* The reflow oven controller is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* The Reflow Oven Control Firmware is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with the reflow oven controller project.
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* If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <reflow-controller/fir-filter.h>
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void fir_filter_init_null(struct fir_filter_fixed *filter)
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{
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uint32_t idx;
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if (!filter)
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return;
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filter->put_idx = 0U;
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for (idx = 0; idx < filter->tap_count; idx++)
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filter->data = 0;
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}
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int32_t fir_filter_process_sample(struct fir_filter_fixed *filter, int32_t sample)
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{
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uint32_t tap_idx;
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uint32_t coeff_idx;
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int32_t output = 0;
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if (!filter)
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return 0;
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/* Store the new data point */
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filter->data[filter->put_idx] = sample;
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coeff_idx = filter->put_idx;
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/* Apply fir taps on data */
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for (tap_idx = 0; tap_idx < filter->tap_count; tap_idx++) {
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output += filter->data[tap_idx] * filter->coefficients[coeff_idx];
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if (coeff_idx)
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coeff_idx--;
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else
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coeff_idx = filter->tap_count-1;
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}
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filter->put_idx++;
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if (filter->put_idx >= filter->tap_count)
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filter->put_idx = 0;
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return output;
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}
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