Core Stalls
3-24
ADSP-2126x SHARC Processor Hardware Reference
• Any read reference to a memory-mapped register located within a
peripheral such as the SPI, SPORTS, IDP, or parallel port requires
a minimum of four cycles; so the minimum stall is three cycles.
• Any reference to a memory-mapped register in a conditional
instruction stalls the processor for one extra cycle (with respect to
an unconditional instruction).
DAG Stalls
One cycle hold on register conflict.
Memory Stalls
One cycle on PM and DM bus access to the same block of internal
memory.
IOP Register Stalls
Read of the IOP registers takes a minimum of four cycles, therefore the
processor stalls for at least three cycles.
DMA Stalls
The following events can cause a DMA stall for the ADSP-2126x:
• One cycle stall if an access to a DMA Parameter register conflicts
with the DMA address generation. For example, writing to or read-
ing from a DMA Parameter register while a register update is
taking place conflicts with DMA chaining.
• n cycles if writing (or reading) to a DMA buffer when the buffer is
full (or empty).
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 ...