Linux/DAC8531: DAC8531

Tool/software: Linux

I had some trouble in using DAC8531 to output an analog voltage to adjust the VCXO.

DAC8531 interfaced to MCU's SPI, Din------>MOSI,SCLK------->SCK,SYNC-------->GPIO, Vout------>Vcontrol(VCXO).sch as below:

I use mode 00, test the OUT:

      Setting D =60000, write 1 times, VOUT output is incorrect, only 0.06V,It looks like no output;

      Setting D =60000, cycle writes, Vout is not a fixed voltage.output jumps form 0V---2.1V.

When I setting Setting D =0xaaaa，The SPI sequence is as follows:

FIGURE 1      Pink------->SCLK, Yellow------>DATA

Code see attachment

Is there have any incorrect?

Tks!Best regards!