DMA RX Buffer Not switching after PACKETS_PROCESSED parameter rollover. It resulted in Audio Distort

Shiva_Bhargav_Yalagonda — Mon, 16 Jun 2025 12:19:39 GMT

Product/MCU: MK70FN1M0XXX15

Toolchain/RTOS: MQX 4.2 RTOS with I2S (SAI) Driver.Received from Freescale as part of development)

Issue Summary
We are experiencing severe audio distortion during long-duration of system up time when using the I2S (SAI) interface with DMA on MQX RTOS. After 7 days of system uptime, the audio from the device becomes distorted or robotic.

Source file: sai_dma_ksai.c.

Note that DMA used to read the voice sample at every 20ms and the size of the packet is 640 bytes( 160 sample in stereo mode, left side 160 sample and right 160samples)

Other information regarding the configurations used in the Software:

DMA buffer counter:4

Buffer size: 160.

IOCTL request to get the DMA buffer pointer: IO_IOCTL_I2S_GET_RX_STATISTICS

IOCTL request used to update the DMA buffer:IO_IOCTL_I2S_UPDATE_RX_STATUS ( We are doubting the issue could be due to PACKETS_PROCESSED%rx.size conditional check before performing the buffer switch)

Questions:
Can NXP confirm if this is known issue in the current I2S SAI DMA driver in MQX?
If yes, what is the fix to resolve this issue? If a fix is available, provide the updated source file.
If not, investigate and provide a way to resolve the issue.
PFA zip file contains audio sample during the issue

Re: DMA RX Buffer Not switching after PACKETS_PROCESSED parameter rollover. It resulted in Audio Dis

Celeste_Liu — Wed, 18 Jun 2025 11:02:07 GMT

Hello @Shiva_Bhargav_Yalagonda ,

Thank you for your post. I've noticed that you have another identical private case. I will focus on resolving your issues within that case. For any updated information, please feel free to reply to me in that private case.
Thank you for your understanding.

BRs,

Celeste

Re: DMA RX Buffer Not switching after PACKETS_PROCESSED parameter rollover. It resulted in Audio Dis

Shiva_Bhargav_Yalagonda — Thu, 19 Jun 2025 12:37:49 GMT

@Celeste_Liu Ok sure

topic Re: DMA RX Buffer Not switching after PACKETS_PROCESSED parameter rollover. It resulted in Audio Dis in Kinetis Microcontrollers

DMA RX Buffer Not switching after PACKETS_PROCESSED parameter rollover. It resulted in Audio Distort

Re: DMA RX Buffer Not switching after PACKETS_PROCESSED parameter rollover. It resulted in Audio Dis

Re: DMA RX Buffer Not switching after PACKETS_PROCESSED parameter rollover. It resulted in Audio Dis