Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
483
Application DMA Unit—Intel
®
81341 and 81342
shows two examples of program synchronization. The left column shows
program synchronization based on individual chain descriptors. Descriptor 1A
generated an interrupt to the processor, while descriptor 2A did not because the
Interrupt Enable bit was clear. The last descriptor nA, generated an interrupt to signify
the end of the chain has been reached. The right column in
shows an
example where the interrupt was generated only on the last descriptor signifying the
end of chain.
Figure 54. Synchronizing to Chained ADMA Operation
Descriptor 1B
Descriptor 2A
Descriptor 2B
..
.
..
.
Descriptor 1A
chain descriptors
chain descriptors
RET
interrupt
procedure
..
.
RET
interrupt procedure
Descriptor nB
..
.
RET
interrupt
procedure
Descriptor nA
..
.
Independent Interrupt after
Completing any Descriptor
Interrupt after Completing
Last Descriptor
No Interrupt on this Descriptor
Optional interrupt
generated to
B6225-01