Rising And Falling Edge Masks - Analog Devices ADSP-21261 SHARC Hardware Reference Manual

DAI Interrupt Controller
cleared. When the
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 latched on the ris-
ing (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-2126x needs information about inter-
rupt 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 elect to use any of 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, both the
rising edge and the falling edge, or neither the rising edge nor the falling
edge. Setting a bit in either the
enables the interrupt level on the rising and falling edges, respectively. For
more information on these registers, see
Figure A-76 on page
12-30
register is read, the low priority latched
DAI_IRPTL_L
DAI_IRPTL_RE
A-172.
ADSP-2126x SHARC Processor Hardware Reference
or
DAI_IRPTL_FE
Figure A-76 on page A-172
registers
and