ADSP-BF537 Blackfin Processor Hardware Reference
4-15
System Interrupts
4. The
SIC_IARx
registers, which map the peripheral interrupts to a
smaller set of general-purpose core interrupts (
IVG7 – IVG15
),
determine the core priority of interrupt A.
5.
ILAT
adds interrupt A to its log of interrupts latched by the core
but not yet actively being serviced.
6.
IMASK
masks off or enables events of different core priorities. If the
IVGx
event corresponding to interrupt A is not masked, the process
proceeds to Step 7.
7. The event vector table (EVT) is accessed to look up the appropriate
vector for interrupt A’s interrupt service routine (ISR).
8. When the event vector for interrupt A has entered the core pipe-
line, the appropriate
IPEND
bit is set, which clears the respective
ILAT
bit. Thus,
IPEND
tracks all pending interrupts, as well as those
being presently serviced.
9. When the interrupt service routine (ISR) for interrupt A has been
executed, the
RTI
instruction clears the appropriate
IPEND
bit.
However, the relevant
SIC_ISR
bit is not cleared unless the inter-
rupt service routine clears the mechanism that generated interrupt
A, or if the process of servicing the interrupt clears this bit.
It should be noted that emulation, reset, NMI, and exception events, as
well as hardware error (
IVHW
) and core timer (
IVTMR
) interrupt requests,
enter the interrupt processing chain at the
ILAT
level and are not affected
by the system-level interrupt registers (
SIC_IWR
,
SIC_ISR
,
SIC_IMASK
,
SIC_IARx
).
If multiple interrupt sources share a single core interrupt, then the inter-
rupt service routine (ISR) must identify the peripheral that generated the
interrupt. The ISR may then need to interrogate the peripheral to deter-
mine the appropriate action to take.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...