DHL Driver
2-88
Important Note:
This driver will no longer be supported in the next
major release of DSP/BIOS. We recommend that you use the IOM
driver interface instead. See the
DSP/BIOS Driver Developer’s Guide
(SPRU616). This driver is still supported in DSP/BIOS 5.32 and will be
supported in any patch releases or minor enhancements to DSP/BIOS
5.32.
Description
The DHL driver manages data streaming between the host and the DSP.
Each DHL device has an underlying HST object. The DHL device allows
the target program to send and receive data from the host through an
HST channel using the SIO streaming API rather than using pipes. The
DHL driver copies data between the stream’s buffers and the frames of
the pipe in the underlying HST object.
Configuring a
DHL
Device
To add a DHL device you must first create an HST object and make it
available to the DHL driver. To do this, use the following syntax:
var myHst = bios.HST.create("myHst");
myHst.availableForDHL = true;
Also be sure to set the mode property to "output" or "input" as needed by
the DHL device. For example:
myHst.mode = "output";
Once there are HST channels available for DHL, you can create a DHL
device object in a configuration script using the following syntax:
var myDhl = bios.DHL.create("myDhl");
Then, you can set this object’s properties to select which HST channel,
of those available for DHL, is used by this DHL device. If you plan to use
the DHL device for output to the host, be sure to select an HST channel
whose mode is output. Otherwise, select an HST channel with input
mode.
Note that once you have selected an HST channel to be used by a DHL
device, that channel is now owned by the DHL device and is no longer
available to other DHL channels.
Configuration
Properties
The following list shows the properties that can be configured in a Tconf
script, along with their types and default values. For details, see the DHL
Driver Properties and DHL Object Properties headings. For descriptions
of data types, see Section 1.4,
DHL Driver
Host link driver