USB protocols over SPI, I2C, Serial?

Hi,

I am interested in if there would be any way to access a Storage medium over a Serial Port and if anyone is familiar with any software that does this?

Example:

Current: Raspberry Pi USB Port --> Arduino M0 micro USB Port

Proposed: Raspberry Pi Serial Port (Tx/Rx) --> Arduino M0 Serial Port.

Purely interested in finding new ways to access the M0 Bootloader Storage Drive (or any other microcontroller with embedded drive) without needing to be attached to USB. Even the Pi GPIO header would be ideal.

Thanks in advance.

Top Replies

michaelkellett over 6 years ago

Software that would do this was readily available in the early days of PCs but since even full speed USB is 100x faster ( and high speed is 4000x faster, super speed 40000x faster and super speed+ 80000x faster) no one bothers with it now !
(I remember Laplink which was sold as software with cables and coudl link PCs by serial port or parallel port)

It would be easy enough to write some code for the Arduino (or other micro) and Pi to copy the data to the Pi, much harder to make it look like a drive to the Pi.

MK
Cancel
Vote Up +6 Vote Down

Sign in to reply

Cancel
genebren over 6 years ago

Not sure if this is the sort of thing you are looking for, but I have used this in a commercial product to host USB thumb drives and printers from a light weight embedded system (https://www.newark.com/ftdi/vnc2-32l1c-reel/controller-usb-vinculum-ii-32lqfp/dp/05AC9620?st=vnc2 ). This allows you to use SPI or serial to read/write on a USB thumb drive. This was a fairly simple way to access the USB drive without have to have full USB stacks running on the host.

Good luck!
Gene
Cancel
Vote Up +2 Vote Down

Sign in to reply

Cancel
wallarug over 6 years ago

Thank you Gene and Michael. I will look into the information provided. Very helpful!
Cancel
Vote Up +2 Vote Down

Sign in to reply

Cancel
abrain over 6 years ago in reply to michaelkellett

I remember using the Kermit protocol http://www.kermitproject.org/kermit.html to transfer files over early cellular modems, doing data downloads and remote software updates on VME based systems.... whilst probably regarded as obsolete, we learnt a lot both using that and later implementing the protocol on newer devices, and it’s a lot easier to implement a simple RS-232 port on a micro controller than a USB stack (although the irony of course is you’d probably use a USB to serial converter on your PC).

A
Cancel
Vote Up +2 Vote Down

Sign in to reply

Cancel
Problemchild over 6 years ago in reply to genebren

I have a few of these I bought at a radio rally at 50p each handy if your controller is serial only but some what redundant in the modern era!
Cancel
Vote Up +1 Vote Down

Sign in to reply

Cancel
Problemchild over 6 years ago in reply to michaelkellett

I think the solution he's proposing is a little more generic and would need to support the USB's multi endpoint provision.
In that case the controller it's self will need to maintain that many to one mapping each potentially with a different class of driver. If you are providing the Micro then it's up to you to write the support. The Vinculo based FTDI devices(Mentioned by Gene) work well in this narrow use case. I think Wallarug needs to consider the exact reason to for doing this!
Cancel
Vote Up +1 Vote Down

Sign in to reply

Cancel