Can nRF52840 USBD read and wrire data usb2.0 fullspeed from SD Card

[Wwing]

Dear team:

  Can nRF52840 USBD read and wrire data usb2.0 fullspeed from SD Card ,If so ,pls release the source code

[Øyvind]

Hello,

Yes, the nRF52840 does support USB 2.0 full speed (12 Mbps) between the board and a computer. Reading and writing to SD Card is handled by the SD Card Library, with an accompanying SD Card Example. We also have a USDB Mass Storage Class example.

Kind regards,
Øyvind

[Wwing]

Hi,team:

How can I test the example without Oscilloscope，so I want to get a result for reading and writing via USBD 2.0 fullspeed up to 1MB/s

[Øyvind]

I'm not sure what you mean. You do not need an oscilloscope for this at all.

What result are you getting?

[Wwing]

Hi Oyvind

I just want to make a experiment,Now I want to test whether the USBD fullspeed can read and write from SD card at 1MB/s

[Øyvind]

Ok, I see. Then I suggest testing with the SD Card Example. In your sdk_config.h (examples\peripheral\fatfs\pca10056\blank\config\sdk_config.h) you can configure:

// <o> APP_SDCARD_FREQ_INIT  - SPI frequency
 
// <33554432=> 125 kHz 
// <67108864=> 250 kHz 
// <134217728=> 500 kHz 
// <268435456=> 1 MHz 
// <536870912=> 2 MHz 
// <1073741824=> 4 MHz 
// <2147483648=> 8 MHz 

#ifndef APP_SDCARD_FREQ_INIT
#define APP_SDCARD_FREQ_INIT 67108864
#endif

// <o> APP_SDCARD_FREQ_DATA  - SPI frequency
 
// <33554432=> 125 kHz 
// <67108864=> 250 kHz 
// <134217728=> 500 kHz 
// <268435456=> 1 MHz 
// <536870912=> 2 MHz 
// <1073741824=> 4 MHz 
// <2147483648=> 8 MHz 

#ifndef APP_SDCARD_FREQ_DATA
#define APP_SDCARD_FREQ_DATA 1073741824
#endif

Note that FREQ_INIT should not exceed 250kHz during an initialization process. See SD Card library for more information.