char SPI_AD5780_Write(unsigned long DATA5){
unsigned short DATA5L,DATA5M,DATA5H;
DATA5H = (unsigned short)(DATA5>>16) & 0x000000FF;
DATA5M = (unsigned short)(DATA5>>8) & 0x000000FF;
DATA5L = (unsigned short)(DATA5) & 0x000000FF;
LDAC=1;
SYNC=0;
spi_tx(DATA5H);
spi_tx(DATA5M);
spi_tx(DATA5L);
SYNC=1;
LDAC=0;
LDAC=1;}
daout0 = 0x00200012;//
SPI_AD5780_Write(daout0);//正常写数据前先定义0010寄存器状态（2=0010）
现在能从串口确认送进去的数是正确的，但得不到想要的电压值（送0为0V，2^18为5V）
电压一直是不变的，CLR RESET都接高电平，上电输出2.8V
