ADSP-2126x SHARC Processor Hardware Reference
5-1
5 MEMORY
The ADSP-2126x contains a large, dual-ported internal memory for single
cycle, simultaneous, independent accesses by the core processor and I/O
processor. The dual-ported memory, in combination with three separate
on-chip buses, allow two data transfers from the core and one transfer
from the I/O processor in a single cycle. Using the I/O bus, the I/O pro-
cessor provides data transfers between internal memory and the DSP’s
communication ports (serial ports and parallel port) without hindering the
DSP core’s access to memory. This chapter describes the DSP’s memory
and how to use it.
The DSP contains up to 2M bits of internal RAM and up to 4M bits of
internal ROM depending on the specific part number
1
. Regardless, each
block can be configured for different combinations of code and data stor-
age. All of the memory can be accessed as 16-bit, 32-bit, 48-bit, or 64-bit
words. The DSP features a 16-bit floating-point storage format that effec-
tively doubles the amount of data that may be stored on-chip. A single
instruction converts the format from 32-bit floating-point to 16-bit
floating-point.
While each memory block can store combinations of code and data,
accesses are most efficient when one block stores data using the DM bus,
(typically block 1) for transfers, and the other block (typically block 0)
stores instructions and data using the PM bus. Using the DM bus and PM
bus with one dedicated to each memory block assures single-cycle execu-
tion with two data transfers. In this case, the instruction must be available
in the cache.
1
For specific memory information, see your ADSP-2126x product-specific data sheet.
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 ...