User`s guide

I/O Overview
6-4
Separate pipes should be used for each data transfer thread, and a pipe
should only have a single reader and a single writer, providing point to point
communication. Often one end of a pipe is controlled by an HWI and the other
end is controlled by an SWI function. Pipes can also transfer data between
two application threads.
Host channel objects allow an application to stream data between the target
and the host. Host channels are statically configured for input or output. Each
host channel is internally implemented using a data pipe object.