LTC2664如何输出?

购买的demo2376A板子,v+,vcc,iovcc,ldac接+5v,REF,gnd,v-,clr,tgp,M4-M0接地,使用msp430的io模拟spi向芯片写数据,但是始终没有输出,请教一下是我的连接线有问题还是我的程序有问题?谢谢各位!

P3DIR |= BIT0+BIT1+BIT2; // P3.0,1 option select,P3.2=CLK
P2DIR |= BIT3; // CS1
P3OUT &= ~(BIT0+BIT1+BIT2);
P2OUT |= BIT3;
Delay_ms(100);
SendData(0,0x600000);
Delay_ms(1000);
SendData(0,0xA0FFFF);

}
void SendData(unsigned int _ch, unsigned long _dac)
{
unsigned int i;
unsigned long data;

data = _dac;

if (_ch == 0)
{
P2OUT &= ~BIT3;
}
else
{
P2OUT &= ~BIT6;
}


for(i = 0; i < 24; i++)
{
if (data & 0x800000)
{
P3OUT |= BIT0;
}
else
{
P3OUT &= ~BIT0;
}
Delay_ms(100);
P3OUT |= BIT2;
data <<= 1;
Delay_ms(100);
P3OUT &= ~BIT2;
}

if (_ch == 0)
{
P2OUT |= BIT3;
}
else
{
P2OUT |= BIT6;
}
}