Sundance SMT6025 v.2.9 - Manual (Page 25)

Version 2.9 Page 25 of 45 SMT6025 User Manual
The DSP loads a handler by sending a command word to the host. Once the
handler is loaded, the DSP communicates directly with the handler.
Receive
command
word
Perform
some action
Replay to
DSP
Host
application
Send
command
Read reply
Interface with
the DSP side
in some way
DSP application
(.app)
Host side handler (.dll)
Host application
(.exe)
DSP side Host side
Figure 9 - Operation of a handler
When the handler receives the DSP’s command word, it performs some action.
This action may or may not involve the host side software.
15.5.1 Handler not interfacing to host software
If the host side code is not involved in the handler, then the handler
performs actions on behalf of the DSP as and when told to do so by the
DSP. These actions occur without the knowledge of the host side
software. An example of this would be the HSCFile library where the
handler (a simple file system) simply performs actions on behalf of the
DSP.
15.5.2 Handler interfacing to host software
In some situations the host application may want to have an interface to
the loaded handler. In this case, the host and the DSP both share the
handler, and the host may wait for the DSP to perform some action to
establish synchronisation. An example of such a handler is the default
handler that is in operation if the DSP does not specifically load a
handler.
User Manual (QCF42); Version 2.9, 22/02/02; © Sundance Multiprocessor Technology Ltd. 2002