ADSP-2126x SHARC Processor Hardware Reference
15-5
System Design
On power-up, the
CLKCFG1–0
pins are used to select ratios of 16:1, 8:1,
and 3:1. After booting, numerous other ratios (slowing or speeding up the
clock) can be selected via software control using the Power Management
Control register.
Power Management Control Register
The ADSP-2126x has a Power Management Control register (
PMCTL
) that
allows programs to determine the amount of power dissipated. This
includes the ability to program the PLL dynamically in software. This fea-
ture eases design for systems that need to use specific clock frequencies or
are sensitive to power consumption.
In addition to changing the clock rate on the fly, The
PMCTL
register also
allows programs to disable the clock source to a particular processor
peripheral completely, (for example the serial ports or the timers), to fur-
ther conserve power. By default, each peripheral block has its internal
CLK
enabled only after it is initialized. Programs can use the
PMCTL
register to
turn the specific peripheral off after the application no longer needs it.
After reset these clocks are not enabled until the peripheral is initialized by
the program.
are examples that show how to use the
Power Management Control register to enable/disable clocking to a
peripheral.
Listing 15-1. Power Management Example
ustat2 = dm(PMCTL);
bit set ustat2 SPIPDN; /* disable internal peripheral clock for
SPI module. SPIPDN is defined as bit 3
of PMCTL*/
dm(PMCTL) = ustat2;
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...