[PIC] Interfacing between USB and SD card voltage levels

[Venkadesh_M]

Hello All, I want to interface between MMC card and USB pen drive with a PIC 16F controller. My problem is voltage level two devices, USB has 5V logic and SD card operates on 3.3V, So how can I do this with out voltage level convertors or anything else am I missing?

I am New to USB, So please give me if you have any sample code for USB interfacing.

Thanks In Advance !!

 

[FvM]

Interface voltage levels is a minor problem. The USB data lines are usually interfaced with a 3.3V supplied driver, 5V processors have an internal 3.3V regultor for this purpose.

To interface a USB pen drive, you need an interface with host/OTG functionaility. PIC16 or PIC18 don't have it. Starting with PIC24.

There's a complete collection of USB and SD card projects in the Microchip Application Libarary, e.g. datalogger on USB pen drive etc.

 

[Venkadesh_M]

The USB data lines are usually interfaced with a 3.3V supplied driver, 5V processors have an internal 3.3V regultor for this purpose.

Sorry I couldn't get it, Please Can you explain further ?

Do you mean Vbus only needs 4.5 to 5.5V but the D lines need only 3.3V for logic ?

 

[FvM]

Do you mean Vbus only needs 4.5 to 5.5V but the D lines need only 3.3V for logic ?

Yes. Review USB spec or datasheet of USB PIC...

 

[Ishaan Karnik]

Sorry I couldn't get it, Please Can you explain further ?

Do you mean Vbus only needs 4.5 to 5.5V but the D lines need only 3.3V for logic ?

Refer this.