ADSP-2126x SHARC Processor Hardware Reference
8-5
Parallel Port
Parallel Data Acquisition Port as Address Pins
PDAP use of AD[15:0] pins.
When bit 26 of the
IDP_PP_CTL
register is
set, the Parallel Data Acquisition Port (PDAP) reads from the parallel
port’s
AD0–15
pins. When this bit is cleared, the PDAP reads data using
DAI pins
DAIP20–5
. To use the parallel port, this bit must be cleared (= 0).
For more information, see “Parallel Data Acquisition Port (PDAP)” on
page 11-6.
Parallel Port Operation
This section describes how the parallel port transfers data. The
SYSCTL
and
PPCTL
registers control the parallel port operating mode.
Basic Parallel Port External Transaction
A parallel port external transaction consists of a combination of an
ALE
cycle and a data cycle, which is either a read or write cycle. The following
section describes parallel port operation as it relates to processor timing.
Refer to the data sheet for your processor for detailed timing
specifications.
An
ALE
cycle is an address latch cycle. In this cycle the
RD
and
WR
signals
are inactive and
ALE
is strobed. The upper 16 bits of the address are driven
onto the
AD15–0
lines, and shortly thereafter the
ALE
pin is strobed, with
AD15–0
remaining valid slightly after de-assertion to ensure a sufficient
hold time for the external latch. The
ALE
pin always remains high for
2 x
CCLK
, irrespective of the data cycle duration values that are set in the
PPCTL
register. The parallel port runs at 1/3 the
CCLK
rate, and so the
ALE
cycle is 3 x
CCLK
. An
ALE
cycle is inserted whenever the upper 16 bits of
address differs from a previous access, as well as after the parallel port is
enabled.
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 ...