Sundance SMT6035 v.2.2 - Manual (Page 23)

Version 2.2 Page 23 of 39 SMT6035 User Manual
You are free to define your own functions in the range 10 – 15. Please refer to
the custom handler section 15.5.4. If this range is insufficient for your
application, you can always pass arguments in the SRAM arguments area to
distinguish your functions.
15.2.1 Protocol between DSP and host
The DSP is always in charge of transfers. This means that the following
protocol must be maintained between the host and the DSP.
The DSP
• Sends a control word to the host.
• Waits for a reply.
The Host
• Waits for a control word from the DSP.
• Performs some action.
• Sends a reply back to the DSP.
The control words are used to synchronize access to memory regions.
They also convey status and error control values. This basic signalling
mechanism is used for both the SRAM and the PCI-type memory
accesses, but can be enhanced to create your own custom protocols.
15.2.2 DSP writing to the host
Before the DSP transfers data to the host, it places the data in the
appropriate memory (PCI or SRAM) and then sends a control word to
the DSP indicating to the host that the data is available. When the host
has replied, the DSP can be sure that the host has processed the data.
Host DSP Section
Waits for control word Writes to shared memory (PCI
or SRAM)
Sends control word to host
Receives control word Waits for host reply Sect 15.6.14
Processes data
Sends reply to DSP Sect 15.6.15
Write operation complete
User Manual - Version 2.2, 04/01/07; © Sundance Italia S.R.L.