ADSP-2126x SHARC Processor Hardware Reference
15-9
System Design
100
s depending on the choice of crystal, operating frequency, loop gain
and capacitor ratios. For details on timing, refer to the product-specific
data sheet.
After the external processor
RESET
signal is deasserted, the PLL starts oper-
ating. The rest of the chip will be held in reset for 4096
CLKIN
cycles after
RESET
is deasserted by an internal reset signal. This sequence allows the
PLL to lock and stabilize. Add one
CLKIN
cycle if
RESET
doesn’t meet setup
requirements with respect to the
CLKIN
falling edge.
Reset Generators
It is important that a processor (or programmable device) have a reliable
active
RESET
that is released once the power supplies and internal clock cir-
cuits have stabilized. The
RESET
signal should not only offer a suitable
delay, but it should also have a clean monotonic edge. Analog Devices has
a range of microprocessor supervisory ICs with different features. Features
include one or more of the following:
• Power-up reset
• Optional manual reset input
Table 15-5. Selecting Core to CLKIN Ratio
Typical Crystal and Clock Oscillators Inputs
12.5
16.67
25
33.3
40
50
Clock Ratios
Core CLK (MHz)
3:1
37.5
50
75
100
120
150
8:1
100
133.36
200
N/A
N/A
N/A
16:1
200
N/A
N/A
N/A
N/A
N/A
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 ...