AnsweredAssumed Answered

AD9552 spi doesn't work

Question asked by shouxi on Jul 13, 2012
Latest reply on Jul 13, 2012 by neilw


     I'm using the AD9552 to generate a 480M clock out, through the spi mode, the XTAL pins are float,  a 20M REF clock is used, the A[2:0],Y[5:0] are keep high, and the RESET pin is kept low,the OUT clock is 625M,I don't know why.(LOCKED PIN is high)

     the REGISTERs I set are as follows:(N=192,P1=2,P2=4)

     0x19: 8'h80

     0x18: 8'h10

     0x17: 8'h00

     0x16: 8'h00

     0x15: 8'h00

     0x14: 8'h1C

     0x13: 8'h00

     0x12: 8'h00

     0x11: 8'hC0

     0x32: 8'hA9

     0x34: 8'hA9

     0x05: 8'h01,


     in addition,I want know how the A[2:0] and Y[5:0] should be  set before and after the SPI  communication


     thans a lot !