ADSP-2126x SHARC Processor Hardware Reference
15-7
System Design
r0 = 4096; /* wait for PLL to lock at new rate
(requirement for modifying multiplier
and setting INDIV bit only) */
lcntr = r0, do pllwait until lce;
pllwait:nop;
ustat2 = dm(PMCTL);
bit clr ustat2 PLLBP;
/* take PLL out of Bypass */
dm(PMCTL) = ustat2;
PMCTL register bit definitions:
/* Power Management Control register (PMCTL) */
#define PLLM8 (BIT_3) // PLL Multiplier 8
#define PLLD8 (BIT_7) // PLL Divisor 8
#define INDIV (BIT_8) // Input Divider
#define DIVEN (BIT_9) // Enable PLL Divisor
#define CLKOUTEN (BIT_12) // Mux select for CLKOUT/RESETOUT
#define PLLBP (BIT_15) // PLL Bypass mode indication
#define SPIPDN (BIT_30) // Shutdown clock to SPI
RESET and CLKIN
The processor receives its clock input on the
CLKIN
pin. The processor uses
an on-chip phase-locked loop (PLL) to generate its internal clock, which is
a multiple of the
CLKIN
frequency (
). Because
the PLL requires some time to achieve phase lock,
CLKIN
must be valid for
a minimum time period during reset before the
RESET
signal can be deas-
serted. For information on minimum clock setup, see the specific
ADSP-2126x data sheet.
CLKIN
frequency
ratios supported by the processor. Note that programs control the PLL
through the
PMCTL
register. This register is described in
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 ...