110 lines
3.0 KiB
C
110 lines
3.0 KiB
C
/*
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* This file is part of the libsigrok project.
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*
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* Copyright (C) 2017 Soeren Apel <soeren@apelpie.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file
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*
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* Conversion helper functions.
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*/
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#include <libsigrok/libsigrok.h>
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#include "libsigrok-internal.h"
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/** @cond PRIVATE */
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#define LOG_PREFIX "conv"
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/** @endcond */
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/**
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* Convert analog values to logic values by using a fixed threshold.
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*
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* @param[in] analog The analog input values.
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* @param[in] threshold The threshold to use.
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* @param[out] output The converted output values; either 0 or 1. Must provide
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* space for count bytes.
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* @param[in] count The number of samples to process.
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*
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* @return SR_OK on success or SR_ERR on failure.
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*/
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SR_API int sr_a2l_threshold(const struct sr_datafeed_analog *analog,
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float threshold, uint8_t *output, uint64_t count)
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{
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float *input;
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if (!analog->encoding->is_float) {
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input = g_try_malloc(sizeof(float) * count);
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if (!input)
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return SR_ERR;
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sr_analog_to_float(analog, input);
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} else
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input = analog->data;
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for (uint64_t i = 0; i < count; i++)
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output[i] = (input[i] >= threshold) ? 1 : 0;
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if (!analog->encoding->is_float)
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g_free(input);
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return SR_OK;
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}
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/**
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* Convert analog values to logic values by using a Schmitt-trigger algorithm.
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*
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* @param analog The analog input values.
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* @param lo_thr The low threshold - result becomes 0 below it.
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* @param hi_thr The high threshold - result becomes 1 above it.
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* @param state The internal converter state. Must contain the state of logic
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* sample n-1, will contain the state of logic sample n+count upon exit.
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* @param output The converted output values; either 0 or 1. Must provide
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* space for count bytes.
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* @param count The number of samples to process.
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*
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* @return SR_OK on success or SR_ERR on failure.
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*/
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SR_API int sr_a2l_schmitt_trigger(const struct sr_datafeed_analog *analog,
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float lo_thr, float hi_thr, uint8_t *state, uint8_t *output,
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uint64_t count)
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{
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float *input;
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if (!analog->encoding->is_float) {
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input = g_try_malloc(sizeof(float) * count);
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if (!input)
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return SR_ERR;
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sr_analog_to_float(analog, input);
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} else
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input = analog->data;
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for (uint64_t i = 0; i < count; i++) {
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if (input[i] < lo_thr)
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*state = 0;
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else if (input[i] > hi_thr)
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*state = 1;
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output[i] = *state;
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}
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if (!analog->encoding->is_float)
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g_free(input);
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return SR_OK;
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}
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