reference code for configuring I2S using SPI on MSP432P411VIPZ

hi Srinivas,

thank you for the sharing the points, i had developed the code for configuring the I2S WRT the link https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/547391?MSP432-I2S-implementation 

whether there are any register to set this particular clock high and low configurations?

2. whether for the audio input can i use the SPI receive interrupt instead of a DMA interrupt?

3. is there any example code where i can change the clock configurations, to set a particular frequency?

for example: i want to set a sampling frequency 3.3024 and my source to be SMCLK, how toset this configuration?

Thank you,

Maniram

hi srinivas, 

the below shared code is used to mimic the SPI to work as a I2S communication:

/* DriverLib Includes */
#include <ti/devices/msp432p4xx/driverlib/driverlib.h>

/* Standard Includes */
#include <stdint.h>
#include <stdbool.h>

/* Statics */

static uint8_t TXData = 0x00;
static DMA_ControlTable DMAControlTable[32];
//![Simple SPI Config]
/* SPI Master Configuration Parameter */
const eUSCI_SPI_MasterConfig spiMasterConfig = {
EUSCI_B_SPI_CLOCKSOURCE_SMCLK, // SMCLK Clock Source
12000000, // SMCLK = 12Mhz
1500000, // SPICLK = 1.5Mhz
EUSCI_B_SPI_MSB_FIRST, // MSB First
EUSCI_B_SPI_PHASE_DATA_CAPTURED_ONFIRST_CHANGED_ON_NEXT, // Phase
EUSCI_B_SPI_CLOCKPOLARITY_INACTIVITY_LOW, // High polarity
EUSCI_B_SPI_3PIN // 3Wire SPI Mode
};
//![Simple SPI Config]
/*************************************
* Interrupt routines declaration
*************************************/
void DMA_Interrupt();

/************************************
* Global variables
************************************/
//Digital audio buffers, read/wrote by DMA
int32_t AudioDataIn;
//Data ready flag, to start audio processing
bool AudioDataReady = false;

int main(void)
{
/* Halting WDT */
WDT_A_holdTimer();

/***********************************************
* Clocking
***********************************************/
//Pins
MAP_GPIO_setAsPeripheralModuleFunctionOutputPin(
GPIO_PORT_PJ, GPIO_PIN3 | GPIO_PIN4, GPIO_PRIMARY_MODULE_FUNCTION);
//Setting the external clock frequency
CS_setExternalClockSourceFrequency(32000, 48000000);
//Starting HFXT in non-bypass mode without a timeout. Before we start
//we have to change VCORE to 1 to support the 48MHz frequency
MAP_PCM_setCoreVoltageLevel(PCM_VCORE1);
MAP_FlashCtl_setWaitState(FLASH_A_BANK0, 2);
MAP_FlashCtl_setWaitState(FLASH_A_BANK1, 2);
CS_startHFXT(false);
//Initializing clock signals */
MAP_CS_initClockSignal(CS_ACLK, CS_LFXTCLK_SELECT, CS_CLOCK_DIVIDER_1); //ACLK=32kHz
MAP_CS_initClockSignal(CS_MCLK, CS_HFXTCLK_SELECT, CS_CLOCK_DIVIDER_1); //MCLK=48kHz
MAP_CS_initClockSignal(CS_SMCLK, CS_HFXTCLK_SELECT, CS_CLOCK_DIVIDER_4); //SMCLK=12MHz

/****************************************************
* EUSCI_B0 SPI (for I2S interface)
****************************************************/
//Pins
MAP_GPIO_setAsPeripheralModuleFunctionInputPin(
GPIO_PORT_P1, GPIO_PIN7, GPIO_PRIMARY_MODULE_FUNCTION); //MISO
MAP_GPIO_setAsPeripheralModuleFunctionOutputPin(
GPIO_PORT_P1, GPIO_PIN5 | GPIO_PIN6, GPIO_PRIMARY_MODULE_FUNCTION); //SCLK, MOSI

//SPI setup
SPI_initMaster(EUSCI_B0_BASE, &spiMasterConfig);

//Enable SPI
SPI_enableModule(EUSCI_A3_BASE);

/* Polling to see if the TX buffer is ready */
while (!(SPI_getInterruptStatus(EUSCI_B0_BASE,EUSCI_B_SPI_TRANSMIT_INTERRUPT)));

/* Transmitting data to slave */
SPI_transmitData(EUSCI_B0_BASE, TXData);

/****************************************************
* DMA (coupled with SPI to make I2S)
****************************************************/
//Enable DMA module
MAP_DMA_enableModule();
MAP_DMA_setControlBase(DMAControlTable);
//Assign channel 6 to EUSCI_A3_TX, channel 7 to EUSCI_A3_RX
DMA_assignChannel(DMA_CH7_EUSCIB0RX3);

//Set RX transfer
DMA_setChannelControl(DMA_CH7_EUSCIB0RX3 | UDMA_PRI_SELECT,
UDMA_SIZE_8 | UDMA_SRC_INC_NONE | UDMA_DST_INC_8 | UDMA_ARB_1);

//Assign DMA interrupt : INT1 to RX channel
DMA_assignInterrupt(INT_DMA_INT1, 7);
//Register interrupt to a defined subroutine
DMA_registerInterrupt(INT_DMA_INT1, DMA_Interrupt);
//Flag set by default, so we have to clear it
DMA_clearInterruptFlag(7);
while (1)
{
if (AudioDataReady == true)
{
//Reset flag
AudioDataReady = false;

}
}
}

//** Interrupt routines */
/* Completion interrupt for DMA */
void DMA_Interrupt()
{
//Set flag for audio processing
AudioDataReady = true;

DMA_setChannelTransfer(
DMA_CH7_EUSCIA3RX | UDMA_PRI_SELECT,
UDMA_MODE_BASIC,
(void*) MAP_SPI_getReceiveBufferAddressForDMA(EUSCI_B0_BASE),
(void*) AudioDataIn, 4);
//Everything is set up, we can enable the two DMA channels
DMA_enableChannel(6);
DMA_enableChannel(7);

DMA_clearInterruptFlag(7);

}

1.here i am not getting how to change the SPI desired frequency 3.3024 Mhz?

2.As i have dont have the board (launchpad MSP432P411), i require some code validation to be done:

whether the DMA interrupt is configured correctly, which is configured on the channel 7, so that on the RX if there is any event the audio sample to be collected ?

whether the AudioDataIn will have the audio samples?

could please help me validating my code.

Thank you,

Maniram