Use case: I2S transmission in DMA mode

This use case shows how to start an I2S transmit operation using DMA and handle half-complete and complete callbacks.

Sequence diagram

@startuml participant "Application" as App participant "I2S" as I2S participant "DMA" as DMA participant "DMAx-IRQHandler" as irq App -> I2S: HAL_I2S_Init() App -> I2S: HAL_I2S_Transmit_DMA() I2S -> DMA: HAL_DMA_Start_IT() "irq" <- : DMAx half complete interrupt irq -> DMA: HAL_DMA_IRQHandler() DMA -> I2S: XferHalfCpltCallback() I2S -> App: HAL_I2S_TxHalfCpltCallback() "irq" <- : DMAx complete interrupt irq -> DMA: HAL_DMA_IRQHandler() DMA -> I2S: XferCpltCallback() I2S -> App: HAL_I2S_TxCpltCallback() @enduml

Code snippet

HAL1

HAL2 

I2S_HandleTypeDef hi2s;
uint8_t aTxBuffer[] = "****SPI - Two Boards communication based on Polling ****";
uint8_t aRxBuffer[BUFFERSIZE];

hI2S.Instance = SPI1;
hI2S.Init.Mode               = I2S_MODE_MASTER_TX;
hI2S.Init.Standard           = I2S_STANDARD_MSB;
hI2S.Init.WSInversion        = I2S_WS_INVERSION_DISABLE;
hI2S.Init.DataFormat         = I2S_DATAFORMAT_24B;
hI2S.Init.MCLKOutput         = I2S_MCLKOUTPUT_DISABLE;
hI2S.Init.AudioFreq          = I2S_AUDIOFREQ_192K;
hI2S.Init.FirstBit           = I2S_FIRSTBIT_MSB;
hI2S.Init.Data24BitAlignment = I2S_DATA_24BIT_ALIGNMENT_LEFT;
hI2S.Init.MasterKeepIOState  = I2S_MASTER_KEEP_IO_STATE_DISABLE;
hI2S.Init.CPOL               = I2S_CPOL_LOW;
HAL_I2S_Init(&hi2s);

__HAL_LINKDMA(hi2s, hdmatx, handle_GPDMA1_Channel1);
HAL_I2S_Transmit_DMA(&hi2s, aTxBuffer, BUFFERSIZE);

hal_i2s_handle_t hi2s;
hal_i2s_config_t i2s_config;
uint8_t aTxBuffer[] = "****SPI - Two Boards communication based on Polling ****";
uint8_t aRxBuffer[BUFFERSIZE];

HAL_I2S_Init(hi2s, HAL_I2S1);
i2s_config.mode            = HAL_I2S_MODE_MASTER_TX;
i2s_config.standard        = HAL_I2S_STANDARD_MSB;
i2s_config.data_format     = HAL_I2S_DATA_FORMAT_24_BIT;
i2s_config.audio_frequency = HAL_I2S_AUDIO_FREQ_192_KHZ;
i2s_config.clock_polarity  = HAL_I2S_CLOCK_POLARITY_LOW;
i2s_config.first_bit       = HAL_I2S_MSB_FIRST;
HAL_I2S_SetConfig(&hi2s, &i2s_config);

HAL_I2S_SetTxDMA(&hi2s, &hGPDMA1_CH1);
HAL_I2S_Transmit_DMA(&hi2s, aTxBuffer, BUFFERSIZE);

Key changes

  1. HAL2 configures I2S via HAL_I2S_SetConfig() before starting the transfer.

  2. HAL2 links the Tx DMA handle to the I2S handle using HAL_I2S_SetTxDMA().