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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 | */ | |
79 | SR_API int sr_a2l_schmitt_trigger(const struct sr_datafeed_analog *analog, | |
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 | } |