Hi,

Question:
Is it possible to build a small device that is identified by the PC as a USB flash memory?

- Regardless of the storage capacity.
- Preferably of small size.
- No matter if it is a read only memory. ROM.

The following figure unleashed my question:

Edit: How?

 

I believe the answer is, "yes", though I have no clue how to go about it.

Apparently you are going to start with a board that has something mounted on it, and that something will be able to answer the interrogation by the computer. It will announce itself as some sort of thumb drive and inform the computer of its capacity. Sounds like some sort of microprocessor chip would be a candidate, but I'm just guessing.

 

I was thinking the same thing. Some microprocessor with:
- A routine loaded for the USB Flash Memory PC driver will auto recognize
- A sequence of bytes with the data

Thanks for reply.

 

There are smarter people than me on this site. Wait 24 hours and see how many can describe the method.

 

I was thinking I would use the following:

• 16 bits microcontroller PIC 24FJ64GB002 @ 32 MHz (16 MIPS)
• 64 KB of Flash and 8KB of RAM. External SPI or I2C memory optional (up to 32MB)
  
• Up to 11 digital I/Os available (Four of them tolerant to 5 volts)
• Up to 4 analog channels.
• ICSP port for debugging and programming. The 3 pins of the ICSP connector can be also used as GP I/Os.

The back side of the board would look something like so:

The complete project info is here.

 

I wanted to track this down (it was not hard, I just Googled the guys name off the card) because this looked like one simple chip as a flash drive. Following the article shows a second IC needed, and that makes me happy as the way I would do this is to use two chips minimum.

(When doing PIC projects one common pattern is to use a USB capable PIC connected to a flash drive. There is library code available to make this work as a flash drive. I then insert my code around this so my app can use the SD card, but one can also connect a PC to download or upload files.)

 

Thank you very much ErnieM!