ADSP-2126x SHARC Processor Hardware Reference
15-15
System Design
reduce the effect of ringing on processor input signals with fast edges,
because the amount of hysteresis that can be used on a CMOS chip is too
small to make a difference. The small amount of hysteresis allowed is due
to restrictions on the tolerance of the VIL and VIH TTL input levels
under worst-case conditions.
Designing for High Frequency Operation
Because the processor can operate at very fast clock frequencies, signal
integrity and noise problems must be considered for circuit board design
and layout. The following sections discuss these topics and suggest various
techniques to use when designing and debugging processor systems.
All synchronous behavior is specified to
CLKIN
. System designers are
encouraged to clock synchronous peripherals with this same clock source
(or a different low-skew output from the same clock driver).
Clock Specifications and Jitter
The clock signal must be free of ringing and jitter. Clock jitter can easily
be introduced into a system where more than one clock frequency exists.
Figure 15-4. Input Pin Hysteresis
GND
V
IL
V
IH
V
DDEXT
V
T
V
T-
V
T+
ENABLES VT-
ENABLES VT+
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 ...