Analog Devices VisualDSP++ 5.0 Service Manual page 412

Using the Device Manager
When using the chained dataflow method, the application can command
the device manager to operate in synchronous mode. Normally, the device
manager operates in asynchronous mode. In asynchronous mode, the
and
dev_Read adi_dev_Write
application before all the buffers passed to the
function have been processed. In synchronous mode, the
Write
and
Read adi_dev_Write
until all buffers provided to the
have been processed. Though seldom used in real-time systems, the device
manager also supports synchronous operation.
As shown in Figure
the chained dataflow method except that after processing the last buffer,
the device manager automatically loops back to the first buffer that was
provided to the device. This operation effectively creates an infinite loop
of buffers. With the chained with loopback method, the application can
provide the buffers at initialization time, allow the device manager to pro-
cess the buffers, and never have to resupply the device manager with
additional buffers. As with the chained dataflow method, each buffer, any
one buffer, none, or all buffers can be tagged to generate a callback to the
application when they are processed.
START
BUFFER 0
Figure 10-4. Chained Buffers With Loopback
10-14
function calls return immediately to the
functions do not return back to the application
adi_dev_Read
10-4, the chained with loopback method is similar to
BUFFER 1
VisualDSP++ 5.0 Device Drivers and System
Services Manual for Blackfin Processors
or
adi_dev_Read
or
adi_dev_Write
. . .
BUFFER N
adi_
adi_dev_
adi_dev_
function