Here I have a application which used AD974 and AD5764, and I want to use MCU's
one SPI Port to control the two chips. That requires the two chips to have Chip
Select, then I can control the two chips separately. AD974 has CS Pin. But for
AD5764, it only have SYNC Pin, so whether the SYNC Pin function is similar with
On the AD5764 the SYNC pin can be treated as a chip select, while SYNC is high
the data and clock signals will be ignored.