Description of Operation
15-8
ADSP-BF537 Blackfin Processor Hardware Reference
Interrupt Processing
Each of the eight timers can generate a single interrupt. The eight result-
ing interrupt signals are routed to the system interrupt controller block for
prioritization and masking. The timer status
(TIMER_STATUS)
register
latches the timer interrupts to provide a means for software to determine
the interrupt source.
To enable interrupt generation, set the
IRQ_ENA
bit and unmask the inter-
rupt source in the
IMASK
and
SIC_IMASK
registers. To poll the
TIMILx
bit
without interrupt generation, set
IRQ_ENA
but leave the interrupt masked
at the system level. If enabled by
IRQ_ENA
, interrupt requests are also gen-
erated by error conditions as reported by the
TOVF_ERRx
bits.
The system interrupt controller enables flexible interrupt handling. All
timers may or may not share the same CEC interrupt channel, so that a
single interrupt routine services more than one timer. In PWM mode,
multiple timers may run with the same period settings and issue their
interrupt requests simultaneously. In this case, the service routine might
clear all
TIMILx
latch bits at once by writing 0x000F 000F to the
TIMER_STATUS
register.
If interrupts are enabled, make sure that the interrupt service routine
(ISR) clears the
TIMILx
bit in the
TIMER_STATUS
register before the
RTI
instruction executes. This ensures that the interrupt is not reissued.
Remember that writes to system registers are delayed. If only a few
instructions separate the
TIMILx
clear command from the
RTI
instruction,
an extra
SSYNC
instruction may be inserted. In
EXT_CLK
mode, reset the
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 ...