USB Embedded Pipe Driver

HCC have implemented an Embedded Pipe for USB which takes the pain out of interfacing a USB device with a host application.

Windows Side

An installable Windows XP driver is provided which creates a standard Comm Object in the PC which can be accessed using simple read/write object methods. Additionally HCC provide a simple configuration application which allows the user to configure the USB connection. Access to the Embedded Pipe Comm Object can be from any program - VC, Perl, VB, VBscript etc.

One sample VC++ application included is an Embedded Pipe Terminal, roughly analogous to HyperTerm, but connected through a raw USB connection.

Embedded Side

The embedded side could not be simpler - the user simply read and writes from the pipe to communicate with the host application. The internals of US are entirely hidden from the developer.

The Reliable File Interface (RFI) is provided as an alternative to USB Mass Storage under Windows.

Mass Storage is a very clean solution when connecting a USB drive to a PC - however when the embedded target is more complex there are cerain limitations to this solution:

• MS writes directly to the target drive - there is no way to synchronize access between the PC and the embedded application which effectively means only the PC or the Embedded target can access the drive at any one time.
• MS limits the possible file system you can use to those directly supported by Windows - generally this means that you use FAT meaning that you are forced to introduce a less reliable file system to your embedded design.

RFI resolves these problems by providing an more NFS-like access to the embedded system - so the embedded system always remains in control of the storage media. Access on the embedded side is through a standard API - so the PC over USB appears simply as another task accessing the file system on the target. In this way any combination of file system types can be used on the embedded target.

RFI is provided as a Windows File System Redirector driver which communicates to the USB device using HCC's USB Embedded Pipe driver.

In look and feel RFI behaves exactly as a standard flash driver in Explorer - it is only the underlying technology that is changed in this solution. This technology gives the developer more flexibility in the solution they choose and gives the possibility of providing more robust products.