i2s driver issuing panicked (LoadProhibited) error when data is passed to it

[Protonerd]

Hi guys,

I have an issue passing data my application reads in from wav files stored on SD-card to the I2S driver. I though I did everything right but I cannot get rid of the error and the board (Adafruit Huzzah32) keeps resetting.

I know that the code does not have major problems as it was developed for another microcontroller with I2S interface originally and verified to be working. Now I wanted to port the same code to the ESP32. I tried my setup with an Audio library (https://github.com/schreibfaul1/ESP32-audioI2S) which worked and therefore I know that wiring-wise my setup can play sound via I2S.

The I2S config looks like this:

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   // configure the ESP32's I2S interface
   m_i2s_config.bits_per_sample					= I2S_BITS_PER_SAMPLE_16BIT;
   m_i2s_config.channel_format					= I2S_CHANNEL_FMT_RIGHT_LEFT;
   // memory (SRAM) allocated to I2S buffer: (bits_per_sample/8)*channels*dma_buf_count*dmu_buf_len
   m_i2s_config.dma_buf_count					= 2; // between 2 and 128 (see error code 283)
   m_i2s_config.dma_buf_len						= I2S_BUF_SIZE*2; // number of I2S samples, multiplied by 2 due to 16bit samples stored on 32bit (L/R)
   m_i2s_config.fixed_mclk						= I2S_PIN_NO_CHANGE;
   m_i2s_config.intr_alloc_flags				= ESP_INTR_FLAG_LEVEL1; // interrupt priority
   m_i2s_config.sample_rate						= 16000;
   m_i2s_config.tx_desc_auto_clear				= true;   // new in V1.0.1
   m_i2s_config.use_apll						= APLL_DISABLE;
   m_i2s_config.mode             				= (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX);
#if ESP_ARDUINO_VERSION_MAJOR >= 2
    m_i2s_config.communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_STAND_I2S); // Arduino vers. > 2.0.0
#else
    // standard I2S format (i.e. not left-justified) means data transmission starts one BCLK cycle after LRCLK transition
    // MAX98357A needs I2S format and MSB first
    m_i2s_config.communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB);
#endif

I2S_BUF_SIZE is 512, which I learned is measured in samples. The samples are 16 bits, my data are stored in L/R format, which takes 32-bit, therefore I reserved double the
space .
I have 3 variables to fetch the samples from SD and pass them to I2S:

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	uint8_t* maBufferA           = NULL;
	uint8_t* maBufferB           = NULL;
	int32_t maMixedI2SSamples[I2S_BUF_SIZE] = {};

The last one holds mixed samples from several wav files, the other 2 get overwritten alternatingly with the content of it and passed to I2S with the i2s_write command:

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   maBufferA = (uint8_t*) heap_caps_calloc(I2S_BUF_SIZE, sizeof(int32_t), MALLOC_CAP_DEFAULT|MALLOC_CAP_INTERNAL|MALLOC_CAP_DMA);

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memcpy(maBufferA, maMixedI2SSamples, sizeof(int32_t)*I2S_BUF_SIZE);

At this command with the i2s_write I get the error and reboot (see below):

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   err = i2s_write((i2s_port_t)I2S_NUM_0, maBufferA, sizeof(int32_t) * I2S_BUF_SIZE, 0, 100);

20:27:42: I2SWavPlayer::StartPlayback>>Pass BufferA to i2s driver.
20:27:42: Guru Meditation Error: Core 1 panic'ed (StoreProhibited). Exception was unhandled.
20:27:42: Core 1 register dump:
20:27:42: PC : 0x400f15ad PS : 0x00060730 A0 : 0x800d37c2 A1 : 0x3ffb1ea0
20:27:42: A2 : 0x00000000 A3 : 0x3ffb2068 A4 : 0x00000004 A5 : 0x00000000
20:27:42: A6 : 0x00000064 A7 : 0x00000000 A8 : 0x800d5428 A9 : 0x3ffb1e90
20:27:42: A10 : 0x00000002 A11 : 0x3f401518 A12 : 0x00000ffc A13 : 0x3ffb5090
20:27:42: A14 : 0x3ffb86fc A15 : 0x000000ff SAR : 0x0000001b EXCCAUSE: 0x0000001d
20:27:42: EXCVADDR: 0x00000000 LBEG : 0x400014fd LEND : 0x4000150d LCOUNT : 0xfffffff1
20:27:42:
20:27:42: ELF file SHA256: 0000000000000000
20:27:42:
20:27:42: Backtrace: 0x400f15ad:0x3ffb1ea0 0x400d37bf:0x3ffb1ed0 0x400d1586:0x3ffb1f10 0x400d19cf:0x3ffb1f30 0x400d722a:0x3ffb1fb0 0x400864c9:0x3ffb1fd0
20:27:42:
20:27:42: Rebooting...


I tried everything I could thing of but the core still throws this error, I would be grateful if someone could give me a helping hand