I want to use th AD9959 together with an Microcontroller to generate 4 signals with different frequencies in the range of about 1MHz-100MHz.
1) As I don't need and further modulation I want to leave out P0-P3 can I simply keep them floating or shopuld I tie them to ground or logic 0?
2)Only 4 DDS are needed so the SYNC_IN and SYNC_OUT and SYNC_CLK Pins aren't needed. Same question here if I can leave the floating or have to tie them to ground/logic 0
3) For Single Bit Serial 3-Wire Mode the SDIO_1 is not used. Same question here, can I leave it floating or tie it to ground/logic 0
4) The IO_Update Pin has to be set high to get the data from the buffer onto the chip. Is it okay to send all SPI commands necessary for operation, store them in the buffer an then make an IO_Update to push everything from the buffer to the chip?