How to speed up USB MSD data transfer in usd- device example?

[pramodk_g_]

Hi everyone,

                      I have modified C:\Freescale\Freescale_MQX_4_0\usb\device\examples\msd example to USB SDcard MSD and its working fine on twrk60n512 . Now I want to increase the speed of data transfer over USB. I defined HIGH_SPEED_DEVICE to 1 to improve the speed, but now the program is going to despatch.s. Will this work correctly or i went wrong somewhere? Can anyone help on this to improve data transfer rate over USB.

Thanks,

Pramod.

[danielchen]

Hi PRAMOD:

I assume you are using usb full speed mode, you can try the following steps

1.- Open the USB libraries project, located on the following path: \...\Freescale MQX 4.0\usb\host\build\cw10\

2.- On this project, search the file “khci.c“ file, in line 964: _mqx_int delay_const = 10;

3.- Change to _mqx_int delay_const = 1;

4.-Search now the file “host_cnfg.h“, and go to line 89: #define USBCFG_DEFAULT_MAX_NAK_COUNT (15)

5.-Change to #define USBCFG_DEFAULT_MAX_NAK_COUNT (150)

6.- Recompile the USB libraries, and then, the BSP and the PSP

Hope it helps

Have a great day,

Daniel

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[pramodk_g_]

Hi Daniel,

                 Thanks for your response. But am using usb device msd application, so will there be any change i if am modifying the usb host section code? .Actually i want to use sdcard as mass storage device, so which example i would use, host or device?   If i want to use device example is there any way speed up the file transfer?

Please reply your thoughts on this

Thanks,

Pramod.

[Kan_Li]

Hi Pramod,

Actually there are two examples available for your reference, one is a mfs demo mounted on a sdcard, you may find it in "C:\Freescale\Freescale_MQX_4_1\mfs\examples\sdcard", and the other is a usb msd device demo for ramdisk, which can be found in "C:\Freescale\Freescale_MQX_4_1\usb\device\examples\msd". and if you looked into the USB stack ver 4.1.1, there is a ready bare matel project for that topic, which can be found in "C:\Freescale\Freescale USB Stack v4.1.1\Source\Device\app\msd\iar_ew\kinetis_60", you may find that demo provide SPI and ESDHC support for SD card, so maybe this demo would be more helpful to speed up your application design:smileyhappy:Please kindly refer to the following for more details.

Hope that helps,

B.R

Kan