HST Module
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called the source) read data from the host to the target. Output channels
(also called the sink) transfer data from the target to the host.
Note:
HST channel names cannot begin with a leading underscore ( _ ).
Each host channel is internally implemented using a data pipe (PIP)
object. To use a particular host channel, the program uses HST_getpipe
to get the corresponding pipe object and then transfers data by calling the
PIP_get and PIP_free operations (for input) or PIP_alloc and PIP_put
operations (for output).
During early development, especially when testing SWI processing
algorithms, programs can use host channels to input canned data sets
and to output the results. Once the algorithm appears sound, you can
replace these host channel objects with I/O drivers for production
hardware built around DSP/BIOS pipe objects. By attaching host
channels as probes to these pipes, you can selectively capture the I/O
channels in real time for off-line and field-testing analysis.
The notify function is called in the context of the code that calls PIP_free
or PIP_put. This function can be written in C or assembly. The code that
calls PIP_free or PIP_put should preserve any necessary registers.
The other end of the host channel is managed by the LNK_dataPump IDL
object. Thus, a channel can only be used when some CPU capacity is
available for IDL thread execution.
HST Manager
Properties
The following global properties can be set for the HST module in the HST
Manager Properties dialog of the DSP/BIOS Configuration Tool or in a
Tconf script:
❏
Object Memory
. The memory segment containing HST objects.
Tconf Name: OBJMEMSEG
Type: Reference
Example:
bios.HST.OBJMEMSEG = prog.get("myMEM");
❏
Host Link Type
. The underlying physical link to be used for host-
target data transfer. If None is selected, no instrumentation or host
channel data is transferred between the target and host in real time.
The Analysis Tool windows are updated only when the target is