Problem with I2S in 24 bits mode

Posted on May 17, 2011 at 13:07

I am trying to use a STM32F103ZE to get data from a CODEC via the I2S interface with 24 bits data.

This is the init sequence :

Code:

I2S_InitStructure.I2S_Mode = I2S_Mode_MasterRx;

I2S_InitStructure.I2S_Standard = I2S_Standard_Phillips;

I2S_InitStructure.I2S_DataFormat = I2S_DataFormat_24b;

I2S_InitStructure.I2S_MCLKOutput = I2S_MCLKOutput_Enable;

I2S_InitStructure.I2S_AudioFreq = I2S_AudioFreq_16k;

I2S_InitStructure.I2S_CPOL = SPI_CPOL_Low;

I2S_Init(SPI2, &I2S_InitStructure);

and the read sequence :

Code:

for (i=0; i<sizeof(buffer)/sizeof(u32); i++)

{

while(SPI_I2S_GetFlagStatus(SPI2,SPI_I2S_FLAG_RXNE)==RESET)

;

buffer[i] = SPI_I2S_ReceiveData(SPI2) << 16;

while(SPI_I2S_GetFlagStatus(SPI2,SPI_I2S_FLAG_RXNE)==RESET)

;

buffer[i] |= SPI_I2S_ReceiveData(SPI2);

}

This is an example of the data I get :

0xFFFCA9FF

0xFFC1A200

0x0006E9FF

0xFEB01A00

0xFFF6D000

...

According to the STM32 Ref Manual, page 549 (Figure 213),

the 8 LSB should be cleared. They are not ...

Am I doing something wrong, or is it a bug in the STM32 I2S implementation ?

Posted on April 01, 2016 at 08:54

hi，

I got the same problem. Have you found the solution to this?