Reading and writing to USB

[Pic_man]

Greetings !

If someone can be so kind and explain me some basics of reading and writing from some USB stick to some PCB device with USB connector.

This USB PCB device will consist of flash memory and PIC24 chip with usb on to go. Flash will be used to store and process data, in the matter: save data, do something, send data to usb stick.

***************************************************
If i look at this throe typical example, than this would look like:
- insert USB stick into USB PCB reader
- read data from USB stick
- do something on USB PSB reader
- write data to external flash of USB PCB reader
- write new data to USB stick.
- disconnect.
**************************************************
Take this in consideration:
- data that should be written to USB: name/lastname/timestamp
- it will be streaming data.

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I know that PIC can be described as USB slave so i need some additional "interface" between PIC and USB but for now i just want to understand the logic behind this.

Thank you!

[FvM]

[pic_man]

Thank you for reply about the chip.
I understand you.

What about the first part of the question.
Is there some algorithm or some example how to make something like this?

[FvM]

I just realized, that I copied the wrong Microchip project name. I meant USB Host - Mass Storage - Thumb Drive Data Logger.

Regarding your question, your asking for common actions of a Mass Storage Device Host. A far as I see, the Microchip example is doing similar things cause it implements a data logger, that can be controlled over a RS232 terminal interface.

But I didn't yet implement the PIC24 host function and I'm not aware of the effort involved with porting the C30 code. I recently ported some other Microchip code to PCD. From this experience, I thinks it's basically feasible.

[Pic_man]

Hi FVM.

PIC24 was set as easy solution but i dont think that this chip be implemented cuz there are cheaper versions. like 18F series...

[FvM]

It's not exavctly clear to me, what you're trying to achieve.

An USB-PIC18 can only act as a device ("Slave"), thus it can't access an USB memory stick, it can emulate an USB memory. CCS has no Mass Storage Device examples, as far as I know, for HID, see the CCS C examples directory.

[Pic_man]

[FvM]

So everything is as said before:

Reading and writing to an USB memory stick doesn't work with a PIC18F.

[Pic_man]

I will use PIC24.

- Is there some microchip example how to make what i have written?
- How to port c30 code to CCS C ?

Thank you for your time.
Regards.

[andrewg]

Apart from using a PIC24 and porting the Microchip Mass Storage Driver, there are a couple of other options. Disclaimer: I've only bookmarked these items - I've never used them! I have no idea how good they are:

Vinculum - A chip implementing a USB host, including mass storage, and serial.

GHI Electronics - They have a chip that supports USB mass storage, and SD cards.

DOSonCHIP - They have a chip that interfaces to SD cards, but not USB mass storage.

All these items should be usable with PIC18s as well as PIC24s. They might even work with PIC16s!
_________________
Andrew

[Pic_man]

Hi Andrew and thank you for reply!
I will use PIC 24 because it has all that i need.

FVM has written that maybe there is a way to port USB example code from microchip to CCS.

If someone knows and wishes to make this, this would be of great use for all of us, because everyone will come to this situation where he will need PIC24 and USB.

Maybe, just setting some test or start program, which can be used in CCS ?

[FvM]

[Pic_man]

[FvM]

I don't see a good way than actually porting the Microchip USB host code to CCS for trial.

[PIC_man]

Where can i download microchip code ?