ADSP-2126x SHARC Processor Hardware Reference
8-3
Parallel Port
Parallel Port Pins
This section describes the pins that the parallel port uses for its operation.
For a complete list of pin descriptions and package pinouts, see the prod-
uct-specific data sheet for your device.
•
Address/Data (AD15–0) pins.
The ADSP-2126x processor pro-
vides time multiplexed address/data pins that are used for
providing both address and data information. The state of the
address/data pins is determined by the 8- or 16-bit operating mode
and the state of the
ALE
,
RD
, and
WR
pins.
•
Read strobe (
RD
) pin.
This output pin is asserted low to indicate a
read operation. Data is latched into the processor using the rising
edge of this signal.
•
Write strobe (
WR
) pin.
This output pin is asserted low to indicate a
write operation. The rising edge of this signal can be used by mem-
ory devices to latch the data from the processor.
•
Address Latch Enable (ALE) pin.
The address latch enable pin is
used to strobe an external latch connected to the address/data pins
(
AD15–0
). The external latch holds the most significant bits (MSBs)
of the external memory address. An
ALE
cycle is inserted for the
first access after the parallel port is enabled and anytime the upper
16 bits of the address change from a previous cycle.
In 8-bit mode, a maximum of 24 bits of external address are facilitated
through latching the upper 16 bits,
EA23–8
, from
AD15–0
into the external
latch during the
ALE
phase of the cycle. The remaining 8 bits of address
EA7–0
are provided through
AD15–8
during the second half of the cycle
when the
RD
or
WR
signal is asserted.
In 16-bit mode, a maximum of 16 bits of external address are facilitated
through latching the upper 16 bits of
AD15–0
from
AD15–0
into the exter-
nal latch during the
ALE
phase of the cycle. The
AD15–0
represent the
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...