STM32F407 HS MSC read\write speed

[boris239955_stm1]

Posted on August 08, 2012 at 15:37

HI,

I did connect STM32F407DESCOVERY to SMSC USB3320 ULPI (USB High Speed mass storage configuration). And uSD curd via SDIO interface. The MCU configured to work in its maximum performance: CPU clk 168Mhz , Enpoint 512byte + aditional endpoint enabled + USB DMA enabled + SDIO DMA Enabled. However the maximum read\write speed for uSD cards of class 6 \class 10 is about 6 Mbyte\sec. When i connect these cards via card reader i get speeds of 20Mbyte at readings. My quastion: Is it maximum available speed (6MB\sec) that can be achieved using STM32F4 in MSC configuration ? Do anybody  get better results ?

[Tesla DeLorean]

Posted on August 08, 2012 at 23:12

No doubt because you have a number of serialized operations:

READ MULTIPLE SECTORS FROM SD CARD, WAIT TILL COMPLETE, SEND DATA OVER USB, WAIT TILL COMPLETE, REPEAT In system where you get 15-20 MBps you've cut out several of these steps, and perhaps a bus or two. Silicon implementation designed for MSC deliver the data directly from the mass storage device to the USB output stream with minimal latency/lag, and a hardware FIFO structure to provide some elasticity. Of the ST examples I've observed you have TWO independent DMA operations, and minimal, if any, overlap between them.

[boris239955_stm1]

Posted on August 09, 2012 at 07:05

Thanks,

I see. So to get maximum performance i need use some bridge usb-sd like

http://www.maxim-ic.com/datasheet/index.mvp/id/6226

To your openion the speed i get 6Mbyte\sec is somthing that suites the STM32F4 limits or i can get more speed (up to 10 maby) ?

[sameena shaikh]

Posted on October 23, 2017 at 11:10

Hi,

How did you measure the read write speed with which it is writing to or reading from sd card??

Thanks & Regards

Sameena Shaikh