Description of Operation
14-16
ADSP-BF537 Blackfin Processor Hardware Reference
Interrupt A and interrupt B operate independently. For example, writing
1 to a bit in the mask interrupt A register does not affect interrupt channel
B. This facility allows GPIOs to generate GPIO interrupt A, GPIO inter-
rupt B, both GPIO interrupts A and B, or neither.
A GPIO interrupt is generated by a logical OR of all unmasked GPIOs for
that interrupt. For example, if
PF0
and
PF1
are both unmasked for GPIO
interrupt channel A, GPIO interrupt A will be generated when triggered
by
PF0
or
PF1
. The interrupt service routine must evaluate the GPIO data
register to determine the signaling interrupt source. Note that interrupt
channel A of port F and interrupt channel A of port G are ORed at system
level as shown in
.
L
When using either rising or falling edge-triggered interrupts, the
interrupt condition must be cleared each time a corresponding
interrupt is serviced by writing 1 to the appropriate bit in the
GPIO clear register.
At reset, all interrupts are masked and disabled.
Similarly to the GPIOs themselves, the mask register can either be written
through the GPIO mask data registers (
PORTxIO_MASKA
,
PORTxIO_MASKB
) or
be controlled by the mask A/mask B set, clear and toggle registers.
The GPIO mask interrupt set registers (
PORTxIO_MASKA_SET
,
PORTxIO_MASKB_SET
) provide an alternative port to manipulate the GPIO
mask interrupt registers. While a direct write to a mask interrupt register
alters all bits in the register, writes to a mask interrupt set register can be
used to set a single or a few bits only. No read-modify-write operations are
required.
The mask interrupt set registers are write-1-to-set registers. All ones con-
tained in the value written to the mask interrupt set register set the
respective bits in the mask interrupt register. The zeroes have no effect.
Writing a one to any bit enables the interrupt for the respective GPIO.
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 ...