Hi,Kevin.G ,,KevinL and kevin.liu,
MY project is using FPGA to control DDS via SPI .
I already sovled the problem with the communication between FPGA and DDS within the help of kevin.G , thank you again!
But there is another tough issue.
No matter in the mode of PC control through USB or in the mode of mannul CONtrol VIA SPI, (refrence clock @ 200Mhz,I aware of the configure of the clock!) the output of the singal has an obvious distortion just >=5 Mhz （It just have a excellent performance @<=1 MHz）.
I THINK that's terrible! Because My project want to generate a sin singal between 4Mhz to 6Mhz ,at a high precision(1 HZ) and at a Frequency hopping ( about 770KHZ ),and more inportantly,the output singal should be Random rather than linear.
So I guess ti's the problem with the power supply? I power the TB1 &TB2 just from the FPGA board (the 3.3V output pins and 1.8 v output pins ).
Further more, could you give me some Feasible suggestions about my project?
Looking forward to your reply timely and comprehensive.
THANK YOU very much!!