ADSP-2126x SHARC Processor Hardware Reference
1-9
Introduction
Processor Internal Buses
The processor core has six buses: PM address, PM data, DM address, DM
data, I/O address, and I/O data. The PM bus is used to fetch instructions
from memory, but may also be used to fetch data. The DM bus can only
be used to fetch data from memory. The I/O bus is used solely by the IOP
to facilitate DMA transfers. In conjunction with the cache, this Super
Harvard Architecture allows the core to fetch an instruction and two
pieces of data in the same cycle that a data word is moved between mem-
ory and a peripheral. This architecture allows dual data fetches, when the
instruction is supplied by the cache.
Bus Capacities.
The PM and DM address buses are both 32 bits wide,
while the PM and DM data buses are both 64 bits wide.
These two buses provide a path for the contents of any register in the pro-
cessor to be transferred to any other register or to any data memory
location in a single cycle. When fetching data over the PM or DM bus, the
address comes from one of two sources: an absolute value specified in the
instruction (direct addressing) or the output of a data address generator
(indirect addressing). These two buses share the same port of the
dual-ported memory.
The second port of the dual-ported memory is dedicated to the I/O
address bus and the I/O data bus to let the I/O processor access internal
memory for DMA without delaying the processor core. The I/O address
bus is 19 bits wide, and the I/O data bus is 32 bits wide.
Data Transfers.
Nearly every register in the processor core is classified as a
universal register (
Ureg
). Instructions allow the transfer of data between
any two universal registers or between a universal register and memory.
This support includes transfers between control registers, status registers,
and data registers in the register file. The PM bus connect (
PX
) registers
permit data to be passed between the 64-bit PM data bus and the 64-bit
DM data bus, or between the 40-bit register file and the PM data bus.
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 ...