DAC Sin Wave.

//Main Loop

  while(1)
  {
    P1OUT |= 0x01; //Turn LED on
    
    for(i=0;i<511;i++)
         spi_send_byte(sinwave[i]); //transfer sine wave down-up
    
    P1OUT &= ~0x01; //Turn LED off
    
    for(i=512;i>1;i--)
         spi_send_byte(sinwave[i]); //transfer sin wave up-down
  }

//sindata.h

#ifndef SINDATA_H_
#define SINDATA_H_


const unsigned int sinwave[]={0,201,402,603,804,1005,1206,1407,1608,1809,2010,2211,2412,\
  2613,2814,3015,3216,3417,3617,3818,4019,4219,4420,4621,4821,5022,5222,5422,5623\
  ,5823,6023,6224,6424,6624,6824,7024,7224,7423,7623,7823,8022,8222,8421,8621,\
  8820,9019,9218,9417,9616,9815,10014,10212,10411,10609,10808,11006,11204,11402\
  ,11600,11798,11996,12193,12391,12588,12785,12983,13180,13376,13573,13770,\
  13966,14163,14359,14555,14751,14947,15143,15338,15534,15729,15924,16119,16314\
  ,16508,16703,16897,17091,17285,17479,17673,17867,18060,18253,18446,18639,18832\
  ,19024,19216,19409,19600,19792,19984,20175,20366,20557,20748,20939,21129,21320\
  ,21510,21699,21889,22078,22268,22457,22645,22834,23022,23210,23398,23586,23774\
  ,23961,24148,24335,24521,24708,24894,25080,25265,25451,25636,25821,26005,26190\
  ,26374,26558,26742,26925,27108,27291,27474,27656,27838,28020,28202,\
  28383,28564,28745,28926,29106,29286,29466,29645,29824,30003,30182,30360,\
  30538,30716,30893,31071,31248,31424,31600,31776,31952,32127,32303,32477,32652,\
  32826,33000,33173,33347,33520,33692,33865,34037,34208,34380,34551,34721,34892\
  ,35062,35231,35401,35570,35738,35907,36075,36243,36410,36577,36744,36910,37076\
  ,37241,37407,37572,37736,37900,38064,38228,38391,38554,38716,38878,39040,39201\
 ,39362,39523,39683,39843,40002,40161,40320,40478,40636,40794,40951,41108,41264,\
 41420,41576,41731,41886,42040,42194,42348,42501,42654,42806,42958,43110,43261,\
 43412,43562,43713,43862,44011,44160,44308,44456,44604,44751,44898,45044,45190,\
 45335,45480,45625,45769,45912,46056,46199,46341,46483,46624,46765,46906,47046\
 ,47186,47325,47464,47603,47741,47878,48015,48152,48288,48424,48559,48694,48828\
 ,48962,49095,49228,49361,49493,49624,49756,49886,50016,50146,50275,50404,50532\
 ,50660,50787,50914,51041,51166,51292,51417,51541,51665,51789,51911,52034,52156\
 ,52277,52398,52519,52639,52759,52878,52996,53114,53232,53349,53465,53581,53697\
 ,53812,53926,54040,54154,54267,54379,54491,54603,54714,54824,54934,55043,55152\
 ,55260,55368,55476,55582,55689,55794,55900,56004,56108,56212,56315,56418,56520\
 ,56621,56722,56823,56923,57022,57121,57219,57317,57414,57511,57607,57703,57798\
 ,57892,57986,58079,58172,58265,58356,58448,58538,58628,58718,58807,58896,58983\
 ,59071,59158,59244,59330,59415,59499,59583,59667,59750,59832,59914,59995,60075\
 ,60156,60235,60314,60392,60470,60547,60624,60700,60776,60851,60925,60999,61072\
 ,61145,61217,61288,61359,61429,61499,61568,61637,61705,61772,61839,61906,61971\
 ,62036,62101,62165,62228,62291,62353,62415,62476,62536,62596,62655,62714,62772\
 ,62830,62886,62943,62998,63054,63108,63162,63215,63268,63320,63372,63423,63473\
 ,63523,63572,63621,63668,63716,63763,63809,63854,63899,63944,63987,64031,64073\
 ,64115,64156,64197,64237,64277,64316,64354,64392,64429,64465,64501,64536,64571\
 ,64605,64639,64672,64704,64735,64766,64797,64827,64856,64884,64912,64940,64967\
 ,64993,65018,65043,65067,65091,65114,65137,65159,65180,65200,65220,65240,65259\
 ,65277,65294,65311,65328,65343,65358,65373,65387,65400,65413,65425,65436,65447\
 ,65457,65467,65476,65484,65492,65499,65505,65511,65516,65521,65525,65528,65531,65533,65535,65535};

#endif /*SINDATA_H_*/

 void spi_send_byte(u16 input) // I guess it's a 16bit byte 
{
  while (!(USICTL1&USIIFG)); //wait until USIIFG is clear-Prev. tran. complete
  P1OUT &= ~(CS_LINE); //Put the SS low
  USISR=input;              //give the input
  USICNT=USI16B+16;    //do 16 bits at a time, cnt = 16.
  while (!(USICTL1&USIIFG)); //block until complete
  P1OUT |= (CS_LINE); //Set SS high - DAC update
}

 typedef unsigned int u16;