Many thanks to BuddyCasino for the base, andriy for the optimizations, and everyone else who started asking questions and looking for answers.
If you're working with the newer API, circa 2020, I'd recommend using I2S_NUM_0 for TX and RX, using i2s_write(...) instead of i2s_write_bytes and i2s_read(...) instead of i2s_read_bytes.
Here are the changes I applied
Code: Select all
i2s_config_t i2s_config_tx = {
.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX),
.sample_rate = sample_rate,
.bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
.channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
.communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
.dma_buf_count = 32,
.dma_buf_len = 64,
.use_apll = false,
.tx_desc_auto_clear = true,
.fixed_mclk = 0};
i2s_config_t i2s_config_rx = {
.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),
.sample_rate = sample_rate,
.bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,
.channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
.communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
.dma_buf_count = 32,
.dma_buf_len = 64,
.use_apll = false,
.tx_desc_auto_clear = true,
.fixed_mclk = 0};
void task_megaphone(void *pvParams)
{
uint16_t buf_len = 1024;
char buf[1024];
struct timeval tv = {0};
struct timezone *tz = {0};
gettimeofday(&tv, &tz);
uint64_t micros = tv.tv_usec + tv.tv_sec * 1000000;
uint64_t micros_prev = micros;
uint64_t delta = 0;
init_i2s();
int cnt = 0;
size_t bytes_written = 0;
while(1)
{
char *buf_ptr_read = buf;
char *buf_ptr_write = buf;
// read whole block of samples
size_t bytes_read = 0;
while(bytes_read == 0) {
i2s_read(
I2S_NUM_0,
buf,
buf_len,
&bytes_read,
portMAX_DELAY);
}
uint32_t samples_read = bytes_read / (I2S_BITS_PER_SAMPLE_32BIT / 8);
// convert 2x 32 bit stereo -> 1 x 16 bit mono
for(int i = 0; i < samples_read; i++) {
buf_ptr_write[0] = buf_ptr_read[2]; // mid
buf_ptr_write[1] = buf_ptr_read[3]; // high
}
// local echo
bytes_written = samples_read * (I2S_BITS_PER_SAMPLE_32BIT / 8);
i2s_write(I2S_NUM_0, buf, bytes_written, &bytes_written, portMAX_DELAY);
i2s_write(I2S_NUM_0, buf, bytes_written, &bytes_written, portMAX_DELAY);
cnt += samples_read;
if(cnt >= 44100) {
gettimeofday(&tv, &tz);
micros = tv.tv_usec + tv.tv_sec * 1000000;
delta = micros - micros_prev;
micros_prev = micros;
printf("%d samples in %" PRIu64 " usecs\n", cnt, delta);
cnt = 0;
}
}
}
andriy wrote: ↑Tue May 30, 2017 6:03 pmWow.... super thanks @BuddyCasinoBuddyCasino wrote:Here is a complete example, I verified it works:Code: Select all
/* * app_main.c * * Created on: 30.03.2017 * Author: michaelboeckling */ #include <stdlib.h> #include <stddef.h> #include <inttypes.h> #include <string.h> #include <stdio.h> #include <stdbool.h> #include <sys/time.h> #include "freertos/FreeRTOS.h" #include "freertos/task.h" #include "freertos/event_groups.h" #include "esp_system.h" #include "esp_log.h" #include "driver/i2s.h" #define TAG "main" static void init_i2s() { const int sample_rate = 44100; /* TX: I2S_NUM_0 */ i2s_config_t i2s_config_tx = { .mode = I2S_MODE_MASTER | I2S_MODE_TX, .sample_rate = sample_rate, .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT, .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT, // 2-channels .communication_format = I2S_COMM_FORMAT_I2S_MSB, .dma_buf_count = 32, // number of buffers, 128 max. .dma_buf_len = 32 * 2, // size of each buffer .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1 // Interrupt level 1 }; i2s_pin_config_t pin_config_tx = { .bck_io_num = GPIO_NUM_26, .ws_io_num = GPIO_NUM_25, .data_out_num = GPIO_NUM_22, .data_in_num = GPIO_NUM_23 }; i2s_driver_install(I2S_NUM_0, &i2s_config_tx, 0, NULL); i2s_set_pin(I2S_NUM_0, &pin_config_tx); /* RX: I2S_NUM_1 */ i2s_config_t i2s_config_rx = { .mode = I2S_MODE_MASTER | I2S_MODE_RX, // Only TX .sample_rate = sample_rate, .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT, // Only 8-bit DAC support .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT, // 2-channels .communication_format = I2S_COMM_FORMAT_I2S_MSB, .dma_buf_count = 32, // number of buffers, 128 max. .dma_buf_len = 32 * 2, // size of each buffer .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1 // Interrupt level 1 }; i2s_pin_config_t pin_config_rx = { .bck_io_num = GPIO_NUM_17, .ws_io_num = GPIO_NUM_18, .data_out_num = I2S_PIN_NO_CHANGE, .data_in_num = GPIO_NUM_5 }; i2s_driver_install(I2S_NUM_1, &i2s_config_rx, 0, NULL); i2s_set_pin(I2S_NUM_1, &pin_config_rx); } void task_megaphone(void *pvParams) { uint16_t buf_len = 1024; char *buf = calloc(buf_len, sizeof(char)); struct timeval tv = {0}; struct timezone *tz = {0}; gettimeofday(&tv, &tz); uint64_t micros = tv.tv_usec + tv.tv_sec * 1000000; uint64_t micros_prev = micros; uint64_t delta = 0; init_i2s(); int cnt = 0; int bytes_written = 0; while(1) { char *buf_ptr_read = buf; char *buf_ptr_write = buf; // read whole block of samples int bytes_read = 0; while(bytes_read == 0) { bytes_read = i2s_read_bytes(I2S_NUM_1, buf, buf_len, 0); } uint32_t samples_read = bytes_read / 2 / (I2S_BITS_PER_SAMPLE_32BIT / 8); // convert 2x 32 bit stereo -> 1 x 16 bit mono for(int i = 0; i < samples_read; i++) { // const char samp32[4] = {ptr_l[0], ptr_l[1], ptr_r[0], ptr_r[1]}; // left buf_ptr_write[0] = buf_ptr_read[2]; // mid buf_ptr_write[1] = buf_ptr_read[3]; // high // right buf_ptr_write[2] = buf_ptr_write[0]; // mid buf_ptr_write[3] = buf_ptr_write[1]; // high buf_ptr_write += 2 * (I2S_BITS_PER_SAMPLE_16BIT / 8); buf_ptr_read += 2 * (I2S_BITS_PER_SAMPLE_32BIT / 8); } // local echo bytes_written = samples_read * 2 * (I2S_BITS_PER_SAMPLE_16BIT / 8); i2s_write_bytes(I2S_NUM_0, buf, bytes_written, portMAX_DELAY); cnt += samples_read; if(cnt >= 44100) { gettimeofday(&tv, &tz); micros = tv.tv_usec + tv.tv_sec * 1000000; delta = micros - micros_prev; micros_prev = micros; printf("%d samples in %" PRIu64 " usecs\n", cnt, delta); cnt = 0; } } } /** * entry point */ void app_main() { printf("starting app_main()\n"); xTaskCreatePinnedToCore(&task_megaphone, "task_megaphone", 16384, NULL, 20, NULL, 0); }
I verify it works flawlessly!
I can also make it work if I use "bits_per_sample : I2S_BITS_PER_SAMPLE_32BIT" as I2S TX config, by changing the code a bit:
Code: Select all
int bytes_read = 0; while(bytes_read == 0) { bytes_read = i2s_read_bytes(I2S_NUM_1, buf, sizeof(buf), portMAX_DELAY); } uint32_t samples_read = bytes_read / (I2S_BITS_PER_SAMPLE_32BIT / 8); for (int i = 0; i < samples_read; i++) { buf_ptr_write[0] = buf_ptr_read[2]; // mid buf_ptr_write[1] = buf_ptr_read[3]; // high } int bytes_written = samples_read * (I2S_BITS_PER_SAMPLE_32BIT / 8); i2s_write_bytes(I2S_NUM_0, (const char*)buf, bytes_written, portMAX_DELAY);
