47 lines
2.1 KiB
C++
47 lines
2.1 KiB
C++
void configure_i2s(int rate) {
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/*keep in mind:
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dma_buf_len * dma_buf_count * bits_per_sample/8 > 4096
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*/
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i2s_config_t i2s_config =
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{
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.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_ADC_BUILT_IN), // I2S receive mode with ADC
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.sample_rate = rate, // sample rate
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.bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT, // 16 bit I2S
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.channel_format = I2S_CHANNEL_FMT_ALL_LEFT, // only the left channel
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.communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB), // I2S format
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.intr_alloc_flags = 1, // none
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.dma_buf_count = 2, // number of DMA buffers
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.dma_buf_len = NUM_SAMPLES, // number of samples
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.use_apll = 0, // no Audio PLL
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};
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adc1_config_channel_atten(ADC_CHANNEL, ADC_ATTEN_11db);
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adc1_config_width(ADC_WIDTH_12Bit);
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i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
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i2s_set_adc_mode(ADC_UNIT_1, ADC_CHANNEL);
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SET_PERI_REG_MASK(SYSCON_SARADC_CTRL2_REG, SYSCON_SARADC_SAR1_INV);
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i2s_adc_enable(I2S_NUM_0);
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}
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/*
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void ADC_Sampling(uint16_t *i2s_buff){
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for (int i = 0; i < B_MULT; i++) {
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//TODO i2s_read_bytes is deprecated, replace with new function
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i2s_read_bytes(I2S_NUM_0, (char*)&i2s_buff[i * NUM_SAMPLES], NUM_SAMPLES * sizeof(uint16_t), portMAX_DELAY);
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}
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}
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*/
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void ADC_Sampling(uint16_t *i2s_buff){
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size_t bytes_read;
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for (int i = 0; i < B_MULT; i++) {
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i2s_read(I2S_NUM_0, (void*)&i2s_buff[i * NUM_SAMPLES], NUM_SAMPLES * sizeof(uint16_t), &bytes_read, portMAX_DELAY);
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for(size_t ix = 0; ix < bytes_read/2; ix++)
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i2s_buff[(i * NUM_SAMPLES) + ix] &= 0x0FFF; // 16bit to 12bit conversion
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}
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}
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void set_sample_rate(uint32_t rate) {
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i2s_driver_uninstall(I2S_NUM_0);
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configure_i2s(rate);
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}
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