Parallel Port Pins
8-4
ADSP-2126x SHARC Processor Hardware Reference
external 16 bits of data during the second half of the cycle when the
RD
or
WR
signal is asserted.
The
ALE
pin is active high by default, but can be set active low via the
PPALEPL
bit (bit 13) in the Parallel Port Control (
PPCTL
) register.
Since
ALE
polarity is active high by default, systems using parallel
port boot mode must use address latching hardware that can pro-
cess this active high signal.
Alternate Pin Functions
The following sections describe how to make the parallel port pins func-
tion as flag pins and how to make the parallel data acquisition port pins
function as address pins. For additional information on pin multiplexing,
see
“Pin Multiplexing” on page 15-2
Parallel Ports as FLAG Pins
Setting (= 1) bit 20 in the
SYSCTL
register, (
PPFLGS
) causes the 16 address
pins to function as
FLAG0
-
FLAG15
. To use the parallel port for data access,
this bit should be cleared (= 0).
For more information, see “System
The ADSP-2126x supports up to 16 general-purpose
FLAG
pins. These
FLAG
signals are multiplexed with other signals, and may be used in several
different ways. If the parallel port is disabled, then the 16 address and data
pins become
FLAG0–FLAG15
. If the parallel port is in use, then these same
16
FLAG
signals can be routed through the SRU, to 16 DAI pins. Finally,
FLAG0–FLAG3
are available on four separate pins. These pins are shared
with
IRQ0–2
and
TIMEXP
.
Configuring the parallel port pins to function as
FLAG0–15
also
causes these four dedicated pins to change to their alternate role,
IRQ0–2
and
TIMEXP
.
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...