Cypress CY25822-2 - Manual (Page 5)

CY25822-2
Document #: 38-07531 Rev. ** Page 5 of 9
CLKOUT and REFOUT Enable Clarification
The CLKOUT enable and REFOUT enable I
2
C register bits are
used to shot-off the CLKOUT and REFOUT clocks individually.
The VCO and crystal oscillator must remain on. A shutdown
clock is driven low. ALL clocks need to be stopped in a
predictable manner. All clocks need to be shutdown without
any glitches or other abnormal behavior while transitioning to
a stopped state. Similarly when CLKOUT or REFOUT is
enabled the clock must start in a predictable manner without
any glitches or abnormal behavior.
REFOUT
PWRDWN#
CLKOUT
Figure 1. Power-down Assertion
P D #
C LK O U T
R E F O U T
< 3.0 m s
Figure 2. Power-down Deassertion
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