SD card 4 bit mode

[chobin]

Hi,

I'm developing an application software for kinetis K20. This application copeis pictures from a USB key to a SD card (class 4).

The final result is very slow, so I decided to enable the SD card 4 bit mode to improve the transfer speed. I tried to do it, but the application doesn't work when it writes a data block.

Please note that the SD code has been generated by processor expert version 10.2.

Does someone activated the 4 bit mode interface of SD card using a kinetis microcontroller? Does it work correctly?

Thank you in advance for your help.

[ZhangJennie]

To investigate your problem correctly and efficiently, please provide us the follows:

1.    your CW version: Start the IDE and click on Help | About CodeWarrior Development Studio. Send me the version and build id.

2.    send the entire sample code folder(include .project, prm,c...) in zip format to me. so that i can test it on my side directly.

3.      error screenshot.

thanks!

[chobin]

Dear Jennie,

I'm using the D4D graphic library of freescale and in some screens I need to load some pictures from SD card.

The operation is very slow and I'd like to improve this speed.

I disconnected some pins of SD card case to verify if it works in 1 bit mode or 4 bit mode and the result is: it works in 1 bit mode.

I think to improve the working speed it should work in 4 bit mode. How I can force it?

Please note that I have not experience on SD cards.

Could you help me?

Many thanks.

Best regards,

Stefano