DGN Driver
Application Program Interface
2-81
Data Streaming
The DGN driver places no inherent restrictions on the size or memory
segment of the data buffers used when streaming from a generator
device. Since generators are fabricated entirely in software and do not
overlap I/O with computation, no more than one buffer is required to
attain maximum performance.
Since DGN generates data “on demand,” tasks do not block when calling
SIO_get, SIO_put, or SIO_reclaim on a DGN data stream. High-priority
tasks must, therefore, be careful when using these streams since lower-
or even equal-priority tasks do not get a chance to run until the high-
priority task suspends execution for some other reason.
DGN Driver Properties
There are no global properties for the DGN driver manager.
DGN Object Properties
The following properties can be set for a DGN device on the DGN Object
Properties dialog in the DSP/BIOS Configuration Tool or in a Tconf script.
To create a DGN device object in a script, use the following syntax:
var myDgn = bios.DGN.create("myDgn");
The Tconf examples assume the myDgn object is created as shown.
❏
comment
. Type a comment to identify this object.
Tconf Name: comment
Type: String
Example:
myDgn.comment = "DGN device";
❏
Device category
. The device category—user, sine, random,
constant, printHex, printInt—determines the type of data stream
produced by the device. A sine, random, or constant device can be
opened for input data streaming only. A printHex or printInt device
can be opened for output data streaming only.
■
user.
Uses a custom function to produce or consume a data
stream.
■
sine.
Produce a stream of sine wave samples.
■
random.
Produces a stream of random values.
■
constant.
Produces a constant stream of data.
■
printHex.
Writes the stream data buffers to the trace buffer in
hexadecimal format.
phase
Numeric
0
rate
Int32
256
fxn
Extern
prog.extern("FXN_F_nop")
arg
Arg
0x00000000
Name
Type
Default (Enum Options)