ADSP-21368 SHARC Processor Hardware Reference 4-69
Digital Audio/Digital Peripheral Interfaces
High and Low Priority Latches
In the ADSP-21367/8/9 and ADSP-2137x processors, a pair of registers
(DAI_IRPTL_H and DAI_IRPTL_L) replace functions normally performed by
the IRPTL register. A single register (DAI_IRPTL_PRI) specifies the latch to
which each of these interrupts are mapped.
Two registers (DAI_IRPTL_RE and DAI_IRPTL_FE) replace the DAI periph-
eral’s version of the IMASK register. As with the IMASK register, these DAI
registers provide a way to specify which interrupts to notice and handle,
and which interrupts to ignore. These dual registers function like IMASK
does, but with a higher degree of granularity.
Signals from the SRU can be used to generate interrupts. For example,
when SRU_EXTMISCA2_INT (bit 30) of DAI_IRPTL_H is set to one, any signals
from the external miscellaneous channel 2 generate an interrupt. If set to
one, DAI interrupts trigger an interrupt in the core and the interrupt latch
is set. A read of this bit does not reset it to zero. The bit is only set to zero
when the cause of the interrupt is cleared. A DAI interrupt indicates the
source (in this case, external miscellaneous A, channel 2), and checks the
IVT for an instruction (next operation) to perform.
The 32 interrupt signals within the interrupt controller are mapped to 2
interrupt signals in the primary interrupt controller of the SHARC pro-
cessor core. The DAI_IRPTL_PRI register specifies if the interrupt controller
interrupt is mapped to the high or low core interrupt (1 = high priority
and 0 = low priority).
The DAI_IRPTL_H register is a read-only register with bits set for every DAI
interrupt latched for the high priority core interrupts. The
DAI_IRPTL_L
register is a read-only register with bits set for every DAI interrupt latched
for the low priority core interrupts. When a DAI interrupt occurs, the low
or high priority core ISR interrogates its corresponding register to deter-
mine which of the 32 interrupt sources to service. When the DAI_IRPTL_H
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