ADSP-2126x SHARC Processor Hardware Reference
8-7
Parallel Port
The order of 8 to 32-bit data packing is shown in
. The first byte
received is [
7:0
], second [
15:8
] and so on. The 16- to 32-bit packing
scheme is shown in the third column of the table.
does not show
ALE
cycles; it shows only the order of the
Writing to an External Device or Memory
The parallel port has a two stage data FIFO for transmitting data (
TXPP
).
The first stage (
TXPP
) is a 32-bit register that receives data from the inter-
nal memory via the DMA controller or a core write. The data in
TXPP
is
moved to the second 32-bit register,
PPSO
. The
PPSO
register provides an
interface to the external pins. Once a full word is transferred out of
PPSO
,
TXPP
data is moved to
PPSO
, if
TXPP
is not empty.
The
PPTRAN
bit of the
PPCTL
register must be set to one in order to
enable writes to it.
The order of 32- to 8-bit data unpacking is shown in
. The first
byte transferred from
PPSO
is [
7:0
], the second [
15:8
] and so on. The
32-bit to 16-bit unpacking scheme is shown in column three of the table.
Table 8-1. Packing Sequence for 32-Bit Data
Transfer
AD7–0, 8-bit to 32-bit
(8-bit bus, LSW first)
AD15–0, 16-bit to 32-bit
(16-bit bus, LSW first)
First
Word 1; bits 7–0
Word 1; bits 15–0
Second
Word 1; bits 15–8
Word 1; bits 31–16
Third
Word 1; bits 23–16
Fourth
Word 1; bits 31–24
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 ...