ADSP-214xx SHARC Processor Hardware Reference
22-7
Power Management
phase-locked loop. Note that the goal in selecting a particular clock ratio
for an application is to provide the highest permissible internal frequency
for a given
CLKIN
frequency. For more information on available clock
rates, see the appropriate product data sheet.
Operating Modes
The following sections provide information on the various options for
clock operation.
Bypass Mode
Bypass mode must be used if any runtime VCO clock change is required.
Setting the
PLLBP
bit bypasses the entire PLL circuitry. In bypass mode,
the core runs at
CLKIN
speed. Once the PLL has settled into the new VCO
frequency, (which may take 4096
CLKIN
cycles) the
PLLBP
bit may be
cleared to release the core from bypass mode.
“Back to Back Bypass” on page 22-17.
Only VCO frequency changes require bypass mode, therefore this
mode is not intended as a standard operating mode.
Table 22-2. Selecting Core to CLKIN Ratio (ADSP-2146x)
Typical Crystal and Clock Oscillators Inputs
12.500
16.667
25.000
33.333
40.000
50.000
Clock Ratios
(CLK_CFG Pins)
Core CLK (MHz
)
1
1 For operational limits for the core clock frequency see the appropriate product data sheet.
6:1
2
2 For ADSP-2147x and ADSP-2148x models, the ratio is 8:1.
N/A
100
150
200
240
300
16:1
200
266.66
400
N/A
N/A
N/A
32:1
400
N/A
N/A
N/A
N/A
N/A
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Содержание SHARC ADSP-214 Series
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Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...