52832 master, through the I2S interface to transmit voice data to the DAC player

[???]

Hi,

Currently I have a problem with the use of 52832 I2S interface to transmit voice, the transmission is not coherent.

Here is my initialization code

	// Enable reception
NRF_I2S->CONFIG.RXEN = (I2S_CONFIG_RXEN_RXEN_Enabled << I2S_CONFIG_RXEN_RXEN_Pos);
// Enable transmission
NRF_I2S->CONFIG.TXEN = (I2S_CONFIG_TXEN_TXEN_Enabled << I2S_CONFIG_TXEN_TXEN_Pos);
// Enable MCK generator
NRF_I2S->CONFIG.MCKEN = (I2S_CONFIG_MCKEN_MCKEN_Enabled << I2S_CONFIG_MCKEN_MCKEN_Pos);
// MCKFREQ = 16 kHz
NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV21 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
// Ratio = 96
NRF_I2S->CONFIG.RATIO = I2S_CONFIG_RATIO_RATIO_96X << I2S_CONFIG_RATIO_RATIO_Pos;
// MCKFREQ = 4 MHz and Ratio = 256 gives sample rate = 15.625 ks/s
// Sample width = 16 bit
NRF_I2S->CONFIG.SWIDTH = I2S_CONFIG_SWIDTH_SWIDTH_16Bit << I2S_CONFIG_SWIDTH_SWIDTH_Pos;
// Alignment = Left
NRF_I2S->CONFIG.ALIGN = I2S_CONFIG_ALIGN_ALIGN_Left << I2S_CONFIG_ALIGN_ALIGN_Pos;
// Format = I2S
NRF_I2S->CONFIG.FORMAT = I2S_CONFIG_FORMAT_FORMAT_I2S << I2S_CONFIG_FORMAT_FORMAT_Pos;
// Use Left
NRF_I2S->CONFIG.CHANNELS = I2S_CONFIG_CHANNELS_CHANNELS_Left << I2S_CONFIG_CHANNELS_CHANNELS_Pos;

// MCK routed to pin 20
NRF_I2S->PSEL.MCK = (20 << I2S_PSEL_MCK_PIN_Pos) | (I2S_PSEL_MCK_CONNECT_Connected << I2S_PSEL_MCK_CONNECT_Pos);
// SCK routed to pin 22
NRF_I2S->PSEL.SCK = (22 << I2S_PSEL_SCK_PIN_Pos) | (I2S_PSEL_SCK_CONNECT_Connected << I2S_PSEL_SCK_CONNECT_Pos);
// LRCK routed to pin 23
NRF_I2S->PSEL.LRCK = (23 << I2S_PSEL_LRCK_PIN_Pos) | (I2S_PSEL_LRCK_CONNECT_Connected <<I2S_PSEL_LRCK_CONNECT_Pos);
// SDOUT routed to pin 24
NRF_I2S->PSEL.SDOUT = (24 << I2S_PSEL_SDOUT_PIN_Pos) | (I2S_PSEL_SDOUT_CONNECT_Connected << I2S_PSEL_SDOUT_CONNECT_Pos);
// SDIN routed on pin 25
NRF_I2S->PSEL.SDIN = (25 << I2S_PSEL_SDIN_PIN_Pos) | (I2S_PSEL_SDIN_CONNECT_Connected << I2S_PSEL_SDIN_CONNECT_Pos);

NRF_I2S->TXD.PTR = *my_tx_buf;
NRF_I2S->RXD.PTR = *my_rx_buf;
NRF_I2S->RXTXD.MAXCNT = MY_BUF_SIZE;

NRF_I2S->ENABLE = 1;

NRF_I2S->TASKS_START = 1;

Use of the data book routines.

Here is my data transfer code.

		NRF_I2S->TXD.PTR = *BufferTx;
	NRF_I2S->EVENTS_TXPTRUPD = 0;

The data captured by the logic analyzer is used to indicate that the data is not coherent.

I would like to ask whether the I2S interface configuration is correct or a reference routines, thank you!

[Jørn]

Hello

I would recommend that you use the I2S driver that comes with the SDK, as it makes it easier to use the hardware.

The code looks for the most part correct, however I am unsure if you are passing the TX and RX buffers correctly. I have tried your code and I have not gotten it to work.

When the buffers are declared as

#define I2S_BUFFER_SIZE     1000
static uint32_t m_buffer_rx[I2S_BUFFER_SIZE];
static uint32_t m_buffer_tx[I2S_BUFFER_SIZE];

you should pass them as

NRF_I2S->TXD.PTR = (uint32_t)m_buffer_tx;
NRF_I2S->RXD.PTR = (uint32_t)m_buffer_rx;
NRF_I2S->RXTXD.MAXCNT = I2S_BUFFER_SIZE;

This is the same way they are passed in the I2S drivers that come with the SDK (see nrf_i2s_rx_buffer_set, in nrf_i2s.h). I have successfully done a loop-back test with this. Keep in mind the EVENTS_TXPTRUPD and EVENTS_RXPTRUPD will trigger once at the beginning of a transfer, before any data has been received.

Please see if this resolves your issue.

Best regards

Jørn Frøysa

[???]

Hi Jørn,

Thank you very much for your help. Your suggestion has been verified and the problem has been further improved.