ADSP-BF537 Blackfin Processor Hardware Reference
14-13
General-Purpose Ports
0x0001 to the GPIO set register drives a logic 1 on the
PF0
pin without
affecting the state of any other
PFx
pins. The GPIO set registers are typi-
cally also used to generate GPIO interrupts by software. Read operations
from the GPIO set registers return the content of the GPIO data registers.
The GPIO clear registers provide an alternative port to manipulate the
GPIO data registers. While a direct write to a GPIO data register alters all
bits in the register, writes to a GPIO clear register can be used to clear
individual bits only. No read-modify-write operations are required. The
clear registers are write-1-to-clear registers. All 1s contained in the value
written to the GPIO clear register clears the respective bits in the GPIO
data register. The 0s have no effect. For example, assume that
PF4
and
PF5
are configured as outputs. Writing 0x0030 to the PORTFIO_C clear reg-
ister drives a logic 0 on the
PF4
and
PF5
pins without affecting the state of
any other
PFx
pins.
L
If an edge-sensitive pin generates an interrupt request, the service
routine must acknowledge the request by clearing the respective
GPIO latch. This is usually performed through the clear registers.
Read operations from the GPIO clear registers return the content of the
GPIO data registers.
The GPIO toggle registers provide an alternative port to manipulate the
GPIO data registers. While a direct write to a GPIO data register alters all
bits in the register, writes to a toggle register can be used to toggle individ-
ual bits. No read-modify-write operations are required. The GPIO toggle
registers are write-1-to-toggle registers. All 1s contained in the value writ-
ten to a GPIO toggle register toggle the respective bits in the GPIO data
register. The 0s have no effect. For example, assume that
PG1
is configured
as an output. Writing 0x0002 to the
PORTGIO_T
toggle register changes the
pin state (from logic 0 to logic 1, or from logic 1 to logic 0) on the
PG1
pin
without affecting the state of any other
PGx
pins. Read operations from the
GPIO toggle registers return the content of the GPIO data registers.
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 ...