ADSP-BF537 Blackfin Processor Hardware Reference
14-15
General-Purpose Ports
The GPIO interrupt sensitivity registers are used to configure each of the
inputs as either a level-sensitive or an edge-sensitive source. When using
an edge-sensitive mode, an edge detection circuit is used to prevent a situ-
ation where a short event is missed because of the system clock rate. The
GPIO interrupt sensitivity register has no effect on GPIOs that are
defined as outputs. The contents of the GPIO interrupt sensitivity regis-
ters are cleared at reset, defaulting to level sensitivity.
The GPIO set on both edges registers are used to enable interrupt genera-
tion on both rising and falling edges. When a given GPIO has been set to
edge-sensitive in the GPIO interrupt sensitivity register, setting the
respective bit in the GPIO set on both edges register to both edges results
in an interrupt being generated on both the rising and falling edges. This
register has no effect on GPIOs that are defined as level-sensitive or as
outputs. See
for information on how the GPIO
set on both edges register interacts with the GPIO polarity and GPIO
interrupt sensitivity registers.
When the GPIO’s input drivers are enabled while the GPIO direction reg-
isters configure it as an output, software can trigger a GPIO interrupt by
writing to the data/set/toggle registers. The interrupt service routine
should clear the GPIO to acknowledge the request.
Each of the three GPIO modules provides two independent interrupt
channels. Identical in functionality, these are called interrupt A and inter-
rupt B. Both interrupt channels have their own mask register which lets
you assign the individual GPIOs to none, either, or both interrupt
channels.
Since all mask registers reset to zero, none of the GPIOs is assigned any
interrupt by default. Each GPIO represents a bit in each of these registers.
Setting a bit means enabling the interrupt on this channel.
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 ...