CY29976AI datasheet(6/10 Pages) CYPRESS

6 / 10 page

CY29976

Document #: 38-07413 Rev. *A

Page 6 of 10

Power Management

The individual output enable/freeze control of the CY29976

allows the user to implement unique power management

schemes into the design. The outputs are stopped in the logic

‘0’ state when the freeze control bits are activated. The serial

input register contains one programmable freeze enable bit for

12 of the 14 output clocks. The QC0 and FB_OUT outputs can

not be frozen with the serial port, this avoids any potential lock

up situation should an error occur in the loading of the serial

data. An output is frozen when a logic ‘0’ is programmed and

enabled when a logic ‘1’ is written. The enabling and freezing

of individual outputs is done in such a manner as to eliminate

the possibility of partial “runt” clocks.

The serial input register is programmed through the SDATA

input by writing a logic ‘0’ start bit followed by 12 NRZ freeze

enable bits. The period of each SDATA bit equals the period of

the free running SCLK signal. The SDATA is sampled on the

rising edge of SCLK.

D10

D11

D0-D3 are the control bits for QA0-QA3, respectively

D4-D7 are the control bits for QB0-QB3, respectively

D8-D10 are the control bits for QC1-QC3, respectively

D11 is the control bit for SYNC

Start

Bit

Figure 2.

CY29976AI Datasheet(PDF) 6 Page - Cypress Semiconductor