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Rev. 1.2.2

External Clock Synchronization Master Slave combination

When an external clock is used, the user will need to setup the master to also have an external

clock in function. All of the same rules apply as in the External clock synchronization, Synchronized

operation as a Slave unit section of this document. There are two ways of synchronizing this,

either the external clock going to both Master/Slave CLK_IN, or CLK_IN can go to the Master, and

the Master can synchronize SYNC_OUT and CLK_OUT to the Slave.

GPIO2

GPIO2

XRP7708

Configured as a

master with

external clock sync

XRP7708

configured

as slave

SYNC_OUT

SYNC_IN

CLK_IN

CLK_IN

GPIO1

GPIO1

Fig. 24: External Clock Synchronization Master Slave Combination

GPIO2

GPIO2

XRP7708

Configured as a

master with

external clock sync

XRP7708

configured

as slave

SYNC_OUT

SYNC_IN

CLK_IN

CLK_IN

GPIO1

GPIO3

CLK_OUT

GPIO1

Fig. 258:Alternative External clock synchronization Master Slave combination

Each switching channel can be programmed to a phase shift of the multiples of 90 degrees [for a 4

phase configuration] or 120 degrees [for a 3 phase configuration]. Two or more of the channels

can use the same phase shift, however, it is preferable to run each channel at separate phases.

The General Purpose Input Output (GPIO) Pins are the basic interface between the XRP7708 and

sometimes convenient to have some of those internal register to be displayed and or controlled by

a single data pin. Besides simple input output functions the GPIO pins can be configured to serve

as external clock inputs. These pins can be programmed using OTP bits or can be programmed

functions that the GPIO can be programmed to do.

NOTE: the GPIO Pins (and all I/Os) should NOT be driven without a 10K resistor when VIN is not

being applied to the IC.