1 /*
2 * Copyright (c) 2021 Nordic Semiconductor ASA
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/kernel.h>
8 #include <zephyr/audio/dmic.h>
9
10 #include <zephyr/logging/log.h>
11 LOG_MODULE_REGISTER(dmic_sample);
12
13 #define MAX_SAMPLE_RATE 16000
14 #define SAMPLE_BIT_WIDTH 16
15 #define BYTES_PER_SAMPLE sizeof(int16_t)
16 /* Milliseconds to wait for a block to be read. */
17 #define READ_TIMEOUT 1000
18
19 /* Size of a block for 100 ms of audio data. */
20 #define BLOCK_SIZE(_sample_rate, _number_of_channels) \
21 (BYTES_PER_SAMPLE * (_sample_rate / 10) * _number_of_channels)
22
23 /* Driver will allocate blocks from this slab to receive audio data into them.
24 * Application, after getting a given block from the driver and processing its
25 * data, needs to free that block.
26 */
27 #define MAX_BLOCK_SIZE BLOCK_SIZE(MAX_SAMPLE_RATE, 2)
28 #define BLOCK_COUNT 4
29 K_MEM_SLAB_DEFINE_STATIC(mem_slab, MAX_BLOCK_SIZE, BLOCK_COUNT, 4);
30
do_pdm_transfer(const struct device * dmic_dev,struct dmic_cfg * cfg,size_t block_count)31 static int do_pdm_transfer(const struct device *dmic_dev,
32 struct dmic_cfg *cfg,
33 size_t block_count)
34 {
35 int ret;
36
37 LOG_INF("PCM output rate: %u, channels: %u",
38 cfg->streams[0].pcm_rate, cfg->channel.req_num_chan);
39
40 ret = dmic_configure(dmic_dev, cfg);
41 if (ret < 0) {
42 LOG_ERR("Failed to configure the driver: %d", ret);
43 return ret;
44 }
45
46 ret = dmic_trigger(dmic_dev, DMIC_TRIGGER_START);
47 if (ret < 0) {
48 LOG_ERR("START trigger failed: %d", ret);
49 return ret;
50 }
51
52 for (int i = 0; i < block_count; ++i) {
53 void *buffer;
54 uint32_t size;
55
56 ret = dmic_read(dmic_dev, 0, &buffer, &size, READ_TIMEOUT);
57 if (ret < 0) {
58 LOG_ERR("%d - read failed: %d", i, ret);
59 return ret;
60 }
61
62 LOG_INF("%d - got buffer %p of %u bytes", i, buffer, size);
63
64 k_mem_slab_free(&mem_slab, buffer);
65 }
66
67 ret = dmic_trigger(dmic_dev, DMIC_TRIGGER_STOP);
68 if (ret < 0) {
69 LOG_ERR("STOP trigger failed: %d", ret);
70 return ret;
71 }
72
73 return ret;
74 }
75
main(void)76 int main(void)
77 {
78 const struct device *const dmic_dev = DEVICE_DT_GET(DT_NODELABEL(dmic_dev));
79 int ret;
80
81 LOG_INF("DMIC sample");
82
83 if (!device_is_ready(dmic_dev)) {
84 LOG_ERR("%s is not ready", dmic_dev->name);
85 return 0;
86 }
87
88 struct pcm_stream_cfg stream = {
89 .pcm_width = SAMPLE_BIT_WIDTH,
90 .mem_slab = &mem_slab,
91 };
92 struct dmic_cfg cfg = {
93 .io = {
94 /* These fields can be used to limit the PDM clock
95 * configurations that the driver is allowed to use
96 * to those supported by the microphone.
97 */
98 .min_pdm_clk_freq = 1000000,
99 .max_pdm_clk_freq = 3500000,
100 .min_pdm_clk_dc = 40,
101 .max_pdm_clk_dc = 60,
102 },
103 .streams = &stream,
104 .channel = {
105 .req_num_streams = 1,
106 },
107 };
108
109 cfg.channel.req_num_chan = 1;
110 cfg.channel.req_chan_map_lo =
111 dmic_build_channel_map(0, 0, PDM_CHAN_LEFT);
112 cfg.streams[0].pcm_rate = MAX_SAMPLE_RATE;
113 cfg.streams[0].block_size =
114 BLOCK_SIZE(cfg.streams[0].pcm_rate, cfg.channel.req_num_chan);
115
116 ret = do_pdm_transfer(dmic_dev, &cfg, 2 * BLOCK_COUNT);
117 if (ret < 0) {
118 return 0;
119 }
120
121 cfg.channel.req_num_chan = 2;
122 cfg.channel.req_chan_map_lo =
123 dmic_build_channel_map(0, 0, PDM_CHAN_LEFT) |
124 dmic_build_channel_map(1, 0, PDM_CHAN_RIGHT);
125 cfg.streams[0].pcm_rate = MAX_SAMPLE_RATE;
126 cfg.streams[0].block_size =
127 BLOCK_SIZE(cfg.streams[0].pcm_rate, cfg.channel.req_num_chan);
128
129 ret = do_pdm_transfer(dmic_dev, &cfg, 2 * BLOCK_COUNT);
130 if (ret < 0) {
131 return 0;
132 }
133
134 LOG_INF("Exiting");
135 return 0;
136 }
137
