DAI/DPI Interrupt Controller
4-70 ADSP-21368 SHARC Processor Hardware Reference
register is read, the high priority latched interrupts are all cleared. When
the
DAI_IRPTL_L register is read, the low priority latched interrupts are all
cleared.
Rising and Falling Edge Masks
For interrupt sources that correspond to waveforms (as opposed to DAI
event signals such as DMA complete or buffer full), the edge of a wave-
form may be used as an interrupt source as well. Just as interrupts can be
generated by a source, interrupts can also be generated and latched on the
rising (or falling) edges of a signal. This concept does not exist in the main
interrupt controller—only in the DAI interrupt controller.
When a signal comes in, the system needs to determine what kind of sig-
nal it is and what kind of protocol, as a result, to service. The preamble
indicates the signal type. When the protocol changes, output (signal) type
is noted.
For audio applications, the ADSP-21367/8/9 and ADSP-2137x processors
need information about interrupt sources that correspond to waveforms
(not event signals). As a result, the falling edge of the waveform may be
used as an interrupt source as well. Programs may select any of these four
conditions:
• Latch on the rising edge
• Latch on the falling edge
• Latch on both the rising and falling edge
The DAI interrupt controller may be configured using three registers.
Each of the 32 interrupt lines can be independently configured to trigger
in response to the incoming signal’s rising edge, its falling edge, or both
the rising edge and the falling edge. Setting a bit in either the
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