i.MXRT1064 EVK SD Card speed issue

[robertsonics]

I'm using a GPIO pin and scope to time how long it takes to read a block of 4 sequential sectors from the microSD card on the MXRT1064 eval board. I'm used to seeing something on the order of 500 us or less on other processors, but am seeing more like 2 ms with this board. After stepping through the code, it's seems clear that a call to USDHC_SetAdmaTableConfig() is returning an error causing DMA to be disabled and the code to fall back to using polling mode.

The microSD card I'm using reports it's using timing mode SDR104, Freq : 198MHz

Any thoughts as to why the DMA is not being used? This happens with the unmodified "sdcard_interrupt" example project.

[Hui_Ma]

Hi,

First of all, sorry for the later reply.

I debug the <sdcard_interrupt> demo with RT1064_EVK, which is using kUSDHC_DmaModeAdma2 mode.

When debug into USDHC_TransferNonBlocking() function at <fsl_usdhc.c> file, the USDHC_SetAdmaTableConfig() function report success status.

I am testing with SDK V2.6.0 software package for RT1064.

Thanks for the attention.

best regards,

Mike