Events and Sequencing
4-26
ADSP-BF535 Blackfin Processor Hardware Reference
Depending on how interrupt sources map to the general-purpose interrupt
inputs of the core, the interrupt service routine may have to interrogate
multiple interrupt status bits to determine the source of the interrupt.
One of the first instructions executed in an interrupt service routine
should read
SIC_ISR
to determine whether more than one of the peripher-
als sharing the input has asserted its interrupt output. The service routine
should fully process all pending, shared interrupts before executing the
RTI, which enables further interrupt generation on that interrupt input.
When an interrupt’s service routine is finished, the
RTI
instruction
clears the appropriate bit in the
IPEND
register. However, the rele-
vant
SIC_ISR
bit is not cleared unless the service routine clears the
mechanism that generated the interrupt.
Many systems need relatively few interrupt-enabled peripherals, allowing
each peripheral to map to a unique core priority level. In these designs,
SIC_ISR
will seldom, if ever, need to be interrogated.
The
SIC_ISR
register is not affected by the state of the Interrupt Mask reg-
ister and can be read at any time. Writes to
SIC_ISR
have no effect on its
contents.
Summary of Contents for ADSP-BF535 Blackfin
Page 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Page 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Page 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Page 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Page 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Page 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Page 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Page 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Page 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...