libsigrok  0.5.2
sigrok hardware access and backend library
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conversion.c
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1 /*
2  * This file is part of the libsigrok project.
3  *
4  * Copyright (C) 2017 Soeren Apel <soeren@apelpie.net>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 /**
21  * @file
22  *
23  * Conversion helper functions.
24  */
25 
26 #include <libsigrok/libsigrok.h>
27 #include "libsigrok-internal.h"
28 
29 #define LOG_PREFIX "conv"
30 
31 /**
32  * Convert analog values to logic values by using a fixed threshold.
33  *
34  * @param[in] analog The analog input values.
35  * @param[in] threshold The threshold to use.
36  * @param[out] output The converted output values; either 0 or 1. Must provide
37  * space for count bytes.
38  * @param[in] count The number of samples to process.
39  *
40  * @return SR_OK on success or SR_ERR on failure.
41  */
42 SR_API int sr_a2l_threshold(const struct sr_datafeed_analog *analog,
43  float threshold, uint8_t *output, uint64_t count)
44 {
45  float *input;
46 
47  if (!analog->encoding->is_float) {
48  input = g_try_malloc(sizeof(float) * count);
49  if (!input)
50  return SR_ERR;
51 
52  sr_analog_to_float(analog, input);
53  } else
54  input = analog->data;
55 
56  for (uint64_t i = 0; i < count; i++)
57  output[i] = (input[i] >= threshold) ? 1 : 0;
58 
59  if (!analog->encoding->is_float)
60  g_free(input);
61 
62  return SR_OK;
63 }
64 
65 /**
66  * Convert analog values to logic values by using a Schmitt-trigger algorithm.
67  *
68  * @param analog The analog input values.
69  * @param lo_thr The low threshold - result becomes 0 below it.
70  * @param lo_thr The high threshold - result becomes 1 above it.
71  * @param state The internal converter state. Must contain the state of logic
72  * sample n-1, will contain the state of logic sample n+count upon exit.
73  * @param output The converted output values; either 0 or 1. Must provide
74  * space for count bytes.
75  * @param count The number of samples to process.
76  *
77  * @return SR_OK on success or SR_ERR on failure.
78  */
80  float lo_thr, float hi_thr, uint8_t *state, uint8_t *output,
81  uint64_t count)
82 {
83  float *input;
84 
85  if (!analog->encoding->is_float) {
86  input = g_try_malloc(sizeof(float) * count);
87  if (!input)
88  return SR_ERR;
89 
90  sr_analog_to_float(analog, input);
91  } else
92  input = analog->data;
93 
94  for (uint64_t i = 0; i < count; i++) {
95  if (input[i] < lo_thr)
96  *state = 0;
97  else if (input[i] > hi_thr)
98  *state = 1;
99 
100  output[i] = *state;
101  }
102 
103  if (!analog->encoding->is_float)
104  g_free(input);
105 
106  return SR_OK;
107 }
Generic/unspecified error.
Definition: libsigrok.h:68
No error.
Definition: libsigrok.h:67
The public libsigrok header file to be used by frontends.
struct sr_analog_encoding * encoding
Definition: libsigrok.h:503
int sr_a2l_threshold(const struct sr_datafeed_analog *analog, float threshold, uint8_t *output, uint64_t count)
Convert analog values to logic values by using a fixed threshold.
Definition: conversion.c:42
int sr_analog_to_float(const struct sr_datafeed_analog *analog, float *outbuf)
Convert an analog datafeed payload to an array of floats.
Definition: analog.c:174
int sr_a2l_schmitt_trigger(const struct sr_datafeed_analog *analog, float lo_thr, float hi_thr, uint8_t *state, uint8_t *output, uint64_t count)
Convert analog values to logic values by using a Schmitt-trigger algorithm.
Definition: conversion.c:79
Analog datafeed payload for type SR_DF_ANALOG.
Definition: libsigrok.h:500
gboolean is_float
Definition: libsigrok.h:511
#define SR_API
Definition: libsigrok.h:121