
ADSP-2126x SHARC Processor Hardware Reference
13-1
13 PRECISION CLOCK
GENERATOR
The Precision Clock Generator (PCG) consists of two units, each of
which generates a pair of signals derived from a clock input signal. The
pair of units, A and B, are identical in functionality and operate inde-
pendently of each other. Each unit generates two signals that are normally
used as a clock frame sync pair. The unit that generates the clock is rela-
tively simple, since digital clock signals are usually regular and
symmetrical. The unit that generates the frame sync output, however, is
designed to be extremely flexible and capable of generating the wide vari-
ety of framing signals needed by the many types of peripherals that can be
connected to the signal routing unit (SRU).
“Signal Routing Unit” on page 12-3.
The core phase locked loop (PLL) has been designed to provide clocking
for the processor core. Although the performance specifications of this
PLL are appropriate for the core, they have not been optimized or speci-
fied for precision data converters where jitter directly translates into time
quantization errors and distortion.
The PCG can accept its clock input either directly from the external oscil-
lator (or discrete crystal) connected to the
CLKIN
/
XTAL
pins or from any of
the 20 DAI pins. This allows a design to contain an external clock with
performance specifications appropriate for the application target.
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 ...