
ADSP-214xx SHARC Processor Hardware Reference
3-127
External Port
Output Clock Generator Programming Model
The following non VCO programming sequence may be used to change
the output generator clock and the core-to-peripheral clock ratio (for
example the SDRAM clock). Note that if your program is only changing
the PLL output divider, programs do not need to wait 4096
CLKIN
cycles
(required only if the PLL multiplier or the
INDIV
bit is modified).
1. Disable the peripheral (SDRAM). Note that the peripherals cannot
be enabled when changing clock ratio.
2. Select the PLL divider by setting the
PLLDx
bits (bits 6–7 in the
PMCTL
register).
3. Select the clock divider (
CCLK
to SDRAM ratio) by setting the ratio
bits (
PMCTL
register).
4. Wait 15
CCLK
cycles. During this time, programs must not execute
any valid instructions.
5. Enable the peripheral (SDRAM).
The new divisor ratios are picked up on the fly and the clocks
smoothly transition to their new values after a maximum of 15 core
clock
CCLK
cycles.
Self-Refresh Mode
The following steps are required when enter and releasing self-refresh
mode.
1. Set the
SDSRF
bit to enter self-refresh mode.
2. Poll the
SDSRA
bit in the SDRAM status register (
SDSTAT
) to deter-
mine if the SDRAM has already entered self-refresh mode.
3. Set the
DSDCTL
bit to freeze
SDCLK
(optional).
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Summary of Contents for SHARC ADSP-214 Series
Page 60: ...Contents lx ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 290: ...Programming Model 4 26 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 656: ...Programming Model 15 40 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...