MIC - Microphone Driver (I2S)
BSP > Thunderboard Sense BSP

Detailed Description

Driver for the Invensense ICS-43434 MEMS Microphone.

Functions

void MIC_deInit (void)
Powers down the MEMS microphone stops the ADC and frees up the DMA channel.
float MIC_getMean (void)
Calculates the average value of the samples in the buffer.
uint16_t * MIC_getSampleBuffer (void)
Gets the sample buffer.
float MIC_getSoundLevel (float *var)
Calculates the sound level.
uint32_t MIC_init (uint32_t fs, uint16_t *buffer, size_t len)
Initializes MEMS microphone and sets up the DMA, ADC and clocking.
bool MIC_isBusy (void)
Checks if the microphone is in use.
void MIC_start (uint32_t nSamples)
Starts taking samples using DMA from the microphone.

Function Documentation

void MIC_deInit ( void )

Powers down the MEMS microphone stops the ADC and frees up the DMA channel.

Returns
None

Definition at line 188 of file mic_i2s.c .

References BOARD_micEnable() , DMADRV_FreeChannel() , DMADRV_StopTransfer() , GPIO_PinModeSet() , gpioModeDisabled , and USART_Reset() .

float MIC_getMean ( void )

Calculates the average value of the samples in the buffer.

Returns
The mean value of the samples in the buffer

Definition at line 254 of file mic_i2s.c .

Referenced by MIC_getSoundLevel() .

uint16_t* MIC_getSampleBuffer ( void )

Gets the sample buffer.

Returns
Returns a pointer to the sample buffer

Definition at line 242 of file mic_i2s.c .

float MIC_getSoundLevel ( float * var )

Calculates the sound level.

Parameters
[out] var The variance of the samples
Returns
The sound level in dB

Definition at line 279 of file mic_i2s.c .

References MIC_getMean() .

uint32_t MIC_init ( uint32_t fs,
uint16_t * buffer,
size_t len
)

Initializes MEMS microphone and sets up the DMA, ADC and clocking.

Parameters
[in] fs The desired sample rate in Hz
[in] buffer Pointer to the sample buffer to store the ADC data
[in] len The size of the sample buffer
Returns
Returns zero on OK, non-zero otherwise

Definition at line 108 of file mic_i2s.c .

References USART_InitSync_TypeDef::autoTx , USART_InitSync_TypeDef::baudrate , BOARD_micEnable() , BOARD_OK , CMU_ClockEnable() , cmuClock_GPIO , DMADRV_AllocateChannel() , DMADRV_Init() , DMADRV_LdmaStartTransfer() , USART_InitI2s_TypeDef::dmaSplit , LDMA_Descriptor_t::dstInc , ECODE_EMDRV_DMADRV_OK , USART_InitSync_TypeDef::enable , USART_InitI2s_TypeDef::format , GPIO_PinModeSet() , gpioModeInput , gpioModePushPull , ldmaCtrlDstIncNone , ldmaCtrlSizeHalf , LDMA_Descriptor_t::size , USART_InitI2s_TypeDef::sync , USART_InitI2s() , USART_INITI2S_DEFAULT , usartEnable , usartI2sFormatW32D16 , and LDMA_Descriptor_t::xfer .

bool MIC_isBusy ( void )

Checks if the microphone is in use.

Returns
Returns true if the DMA is busy taking microphone samples

Definition at line 320 of file mic_i2s.c .

void MIC_start ( uint32_t nSamples )

Starts taking samples using DMA from the microphone.

Parameters
[in] nSamples The number of the samples to take
Returns
None

Definition at line 222 of file mic_i2s.c .