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ADSP-BF537 Blackfin Processor Hardware Reference
14-9
General-Purpose Ports
The
PORT_MUX
register controls the muxing schemes of port F, port G and
port J.
The function enable register (
PORTF_FER
,
PORTG_FER
,
PORTH_FER
) enables
the peripheral functionality for each individual pin of port x.
Performance/Throughput
The
PFx
,
PGx
, and
PHx
pins are synchronized to the system clock (
SCLK
).
When configured as outputs, the GPIOs can transition once every system
clock cycle.
When configured as inputs, the overall system design should take into
account the potential latency between the core and system clocks. Changes
in the state of port pins have a latency of 3
SCLK
cycles before being detect-
able by the processor. When configured for level-sensitive interrupt
generation, there is a minimum latency of 4
SCLK
cycles between the time
the signal is asserted on the pin and the time that program flow is inter-
rupted. When configured for edge-sensitive interrupt generation, an
additional
SCLK
cycle of latency is introduced, giving a total latency of 5
SCLK
cycles between the time the edge is asserted and the time that the
core program flow is interrupted.
Description of Operation
The operation of the general-purpose ports is described in the following
sections.
Operation
The GPIO pins on port F, port G, and port H can be controlled individu-
ally by the function enable registers (
PORTx_FER
). With a control bit in
these registers cleared, the peripheral function is fully decoupled from the
pin. It functions as a GPIO pin only. To drive the pin in GPIO output
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
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Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
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Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...