Analog Devices VisualDSP++ 5.0 Service Manual page 425

•
CallbackType
the application desires and contains one of the following:
•
ADI_DEV_CIRC_NO_CALLBACK
•
ADI_DEV_CIRC_SUB_BUFFER
each sub-buffer
•
ADI_DEV_CIRC_FULL_BUFFER
tion of the entire buffer
•
pAdditionalInfo
This field is not used for most device drivers. For information
describing whether this field is used by the particular device driver,
refer to the documentation specific to the device driver, located in
the
.../Blackfin/doc
For example, the following code fragment prepares and submits a circular
buffer for transmission out through the device driver via the
function. The buffer describes a contiguous block of 1024 bytes
Write()
of memory that is divided into 8 sub-buffers of 128 bytes each. The driver
calls the application back after each sub-buffer is processed. Once data-
flow is enabled, the driver repeatedly processes the circular buffer until
dataflow is terminated.
#define SUB_BUFFERS
#define SUB_BUFFER_ELEMENTS (128)
static u8 Data[SUB_BUFFERS * SUB_BUFFER_ELEMENTS];
static ADI_DEV_CIRCULAR_BUFFER Buffer;
// create buffer for the driver to process
Buffer.Data
Buffer.ElementWidth
Buffer.SubBufferCount
Buffer.SubBufferElementCount = SUB_BUFFER_ELEMENTS;
VisualDSP++ 5.0 Device Drivers and System
Services Manual for Blackfin Processors
– This field specifies the frequency of callbacks that
– This field is a device driver-dependent value.
subdirectory.
(8)
= Data;
= 1;
= SUB_BUFFERS;
Device Driver Manager
– No callbacks
– Call back after completion of
– Call back only after comple-
// storage for data
// the actual buffer
adi_dev_
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