some problem when reading the register

[chen1011]

I'm a newbie in programming AD9954 with arduino
here is my code

include <SPI.h>

include <AD9954.h>

AD9954 DDS( 10, 6, 5, 8, 9, 7);

void setup(){
SPI.begin();
Serial.begin(9600);
SPI.setClockDivider(4);
SPI.setDataMode(SPI_MODE0);
delay(500); // let things get set up...
DDS.initialize(400000000);

}

void loop(){

DDS.setFreq(25000000);
digitalWrite(10,LOW);
SPI.transfer(0x80);
Serial.print(SPI.transfer(0x00));
digitalWrite(10,HIGH);
delay(1000);
}

but the only thing I can get from the serial monitor is 0

is there any problem with my code?
thank you : )