SAI_TxSetBitClockRate parameter questions

davenadler — Wed, 27 Nov 2024 01:48:18 GMT

I'm trying to set up SAI (send only, as master).
But I'm confused by the SAI_TxSetBitClockRate parameters, documented as:

/*! * brief Transmitter bit clock rate configurations. * * param base SAI base pointer. * param sourceClockHz, bit clock source frequency. * param sampleRate audio data sample rate. * param bitWidth, audio data bitWidth. * param channelNumbers, audio channel numbers. */ void SAI_TxSetBitClockRate( I2S_Type *base, uint32_t sourceClockHz, uint32_t sampleRate, uint32_t bitWidth, uint32_t channelNumbers)

1) What is uint32_t channelNumbers?
In the code this seems to be used as numberOfChannels (ie 2 for stereo):

uint32_t bitClockFreq = sampleRate * bitWidth * channelNumbers;

2) What is uint32_t sourceClockHz?
Is this just the module's clock input, as generated by the clock tool, ie

#define BOARD_BOOTCLOCKRUN_SAI1_CLK_ROOT 63529411UL

Thanks in advance,
Best Regards, Dave

回复： SAI_TxSetBitClockRate parameter questions

Gavin_Jia — Wed, 27 Nov 2024 08:46:50 GMT

Hi @davenadler ,

Thanks for your interest in NXP MIMXRT series!

1) What is uint32_t channelNumbers?
In the code this seems to be used as numberOfChannels (ie 2 for stereo):

>> Yes, you are right.

2) What is uint32_t sourceClockHz?
Is this just the module's clock input, as generated by the clock tool, ie

>> Yes. It is the clock frequency of the SAI peripheral. It is used to configure the appropriate BCLK.

topic SAI_TxSetBitClockRate parameter questions in i.MX RT Crossover MCUs

SAI_TxSetBitClockRate parameter questions

回复： SAI_TxSetBitClockRate parameter questions