miniresnet NbrOfBytes > 65535U error on B-U585I-IOT02A

[M_Kuro]

Hello,

I am trying to use miniresnet provided at [miniresnet] on B-U585I-IOT02A board.

I am using STM32CubeIDE locally, following the instruction from [wiki] for setting up software environment, and from [configuration] and [deployment] documentation for configuration and deployment. I generated the C code using the CLI and am viewing inference results via the Serial Monitor.

However, when I run inference, I encounter an error with code -4.It appears to come from the following condition "NbrOfBytes > 65535U" in "./STM32Cube/Projects/stm32ai-modelzoo-services/application_code/sensing_free_rtos/STM32U5/Drivers/BSP/B-U585I-IOT02A/b_u585i_iot02a_audio.c".

int32_t BSP_AUDIO_IN_Record(uint32_t Instance, uint8_t *pData, uint32_t NbrOfBytes)
{
  int32_t  status = BSP_ERROR_NONE;

  if ((Instance >= AUDIO_IN_INSTANCES_NBR) || (pData == NULL) || (NbrOfBytes > 65535U))
  {
    status = BSP_ERROR_WRONG_PARAM;
  }
...

In my case, NbrOfBytes is calculated to be 66816, which exceeds the 65535 limit. This value comes from the following macro definitions:

#define CTRL_X_CUBE_AI_SPECTROGRAM_PATCH_LENGTH  ((CTRL_X_CUBE_AI_SPECTROGRAM_COL-1)*CTRL_X_CUBE_AI_SPECTROGRAM_HOP_LENGTH + CTRL_X_CUBE_AI_SPECTROGRAM_NFFT)
/* dpu_config.h */

/* Exported constants --------------------------------------------------------*/
#define AUDIO_HALF_BUFF_SIZE (CTRL_X_CUBE_AI_SPECTROGRAM_PATCH_LENGTH*2)
#define AUDIO_BUFF_SIZE      (AUDIO_HALF_BUFF_SIZE*2)
/* preproc_dpu.h */

The values used are derived from the miniresnet configuration YAML (miniresnet_1stacks_64x50_tl_config.yaml):
CTRL_X_CUBE_AI_SPECTROGRAM_COL=50U (patch_length)
CTRL_X_CUBE_AI_SPECTROGRAM_HOP_LENGTH=320U (hop_length)
CTRL_X_CUBE_AI_SPECTROGRAM_NFFT=1024U (window_length)

Which leads to:

CTRL_X_CUBE_AI_SPECTROGRAM_PATCH_LENGTH = (50 - 1) * 320 + 1024 = 15824 samples
AUDIO_BUFF_SIZE = 15824 * 2 * 2 = 66816

This exceeds the uint16_t limit expected by BSP_AUDIO_IN_Record().

? Question

Is the miniresnet model (with 64x50 input shape) supposed to work on the B-U585I-IOT02A board?
If not, are there recommended modifications to buffer sizes, model configuration, or audio acquisition to make it compatible?

Any guidance would be greatly appreciated. Thank you!

[Julian E. · Accepted solution]

Hello @M_Kuro,

Is the miniresnet model (with 64x50 input shape) supposed to work on the B-U585I-IOT02A board?

> the miniresnet model is not validated on B-U585I-IOT02A board.

If not, are there recommended modifications to buffer sizes, model configuration, or audio acquisition to make it compatible?

> The acquisition have been simplified, using double buffers and DMA . The limitation comes from DMA byte counter.
> You may program more than one DMA transfert to feed the model, Two In your case.

Have a good day,

Julian