Code:
void WriteCMD( uint CMD ) <-uint CMD takes in an unsigned integer
{
    uchar n=16; <-unsigned character (byte) set to 16
    SCK=0; <- SCK to logic low
    nSEL=0; <- nSEL to logic low
    while(n--) <- while/wend loop, n gets decremented by 1 each time thru
    {
        if(CMD&0x8000) <- if high bit of CMD is set then
          Write1(); <-call the Write1() sub
        else
          Write0(); <-otherwise do this one
        CMD=CMD<<1; <-shift it left by one
    }
    SCK=0; <- SCK to logic low
    nSEL=1; <- nSEL to logic high
}
I might be totally wrong...not that familiar with C...but to me this means:

Code:
WriteCMD:
n = 16 : SCK = 0 : nSEL = 0
for nn = 16 to 0 step -1
if cmd.15 = 1 then
gosub write1
else
gosub write0
endif
cmd = cmd << 1 : sck = 0 : nSel = 1 : return

Write0:
SDI = 0 : SCK = 0 : pauseus 16 : SCK = 1 : return

Write1:
SDI = 1 : SCK = 0 : pauseus 16 : SCK = 1 : return
And your issue might've been that you didn't turn the nSEL line on/off before writing out to the port...unless you didn't include that part in the posts.