SD_read.h

00001 // It takes 276us to read from sd card and write in 112 buffer
00002 
00003 //~ #include"SDcard.h"
00004 #define T_frames 39
00005 unsigned char buffer_112_counter,sent_tm = 0;
00006 int disk_read(uint8_t *, uint64_t),j;
00007 bool new_session = true;
00008 bool last_buffer = false;
00009 bool first_block = true;
00010 bool last_block =false;
00011 bool repeat_T_frame = false;
00012 unsigned int counter_in_block=0,diff_prev=0;
00013 unsigned char  EOS_counter = 0;
00014 unsigned char enable_T_frame = false;
00015 unsigned long long int start_block_num ;           // Read from TC
00016 unsigned long long int end_block_num ;            // Read from TC
00017 unsigned long long int Number_of_blocks_to_read ;
00018 unsigned long long int block_counter = 0;
00019 unsigned char buffer_512[512], buffer_112[112],counter_in_S_frame=0,counter_in_SCH=0;
00020 unsigned char S_frame[48]={0x46,0x9D,0xFB,0xF0,0xD2,0xBA,0x89,0xE4,0x46,0x9D,0xFB,0xF0,0xD2,0xBA,0x89,0xE4,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
00021 //unsigned char SCH[40] = {0x0A,0x3F,0x46,0xB4,0x00};
00022 unsigned char EoS[120];
00023 unsigned char make_EOS_flag =true;
00024 
00025 void differential_encode(unsigned char* ptr, int length){
00026     
00027         for(int i=0; i<length;i++){
00028         
00029             unsigned char s = ptr[i] , t;
00030             t = s ^ (s >> 1);
00031             (diff_prev == 0) ? t=t^0x00 : t=t^0x80 ;
00032             diff_prev = int(s & 0x01);
00033             ptr[i] = t;
00034         }
00035         
00036     } 
00037 
00038 void make_EOS()
00039 {       
00040 
00041 for(int i = 0 ; i < 24 ; ++i){
00042                     EoS[i] = 0x00;
00043             }
00044     
00045             //~ S-FRAME [1]
00046             //~ first two bits of S-FRAME
00047             EoS[23] = 0x01;
00048             
00049             EoS[24] = 0x1a;
00050             EoS[25] = 0x77;
00051             EoS[26] = 0xef;
00052             EoS[27] = 0xc3;
00053             EoS[28] = 0x4a;
00054             EoS[29] = 0xea;
00055             EoS[30] = 0x27;
00056             EoS[31] = 0x91;
00057             EoS[32] = 0x1a;
00058             EoS[33] = 0x77;
00059             EoS[34] = 0xef;
00060             EoS[35] = 0xc3;
00061             EoS[36] = 0x4a;
00062             EoS[37] = 0xea;
00063             EoS[38] = 0x27;
00064             EoS[39] = 0x90;
00065     
00066             for(int i = 40 ; i < 72 ; ++i){
00067                 EoS[i] = 0x00;
00068             }
00069             
00070             //~ S-FRAME [2]
00071             //~ first two bits of S-FRAME
00072             EoS[71] = 0x01;
00073             
00074             EoS[72] = 0x1a;
00075             EoS[73] = 0x77;
00076             EoS[74] = 0xef;
00077             EoS[75] = 0xc3;
00078             EoS[76] = 0x4a;
00079             EoS[77] = 0xea;
00080             EoS[78] = 0x27;
00081             EoS[79] = 0x91;
00082             EoS[80] = 0x1a;
00083             EoS[81] = 0x77;
00084             EoS[82] = 0xef;
00085             EoS[83] = 0xc3;
00086             EoS[84] = 0x4a;
00087             EoS[85] = 0xea;
00088             EoS[86] = 0x27;
00089             EoS[87] = 0x90;
00090             
00091             for(int i = 88 ; i < 120 ; ++i){
00092                 EoS[i] = 0x00;
00093             }
00094     
00095 }
00096 
00097 void send_tm_from_SD_card(){
00098     
00099     
00100     if(make_EOS_flag == true){
00101         make_EOS();
00102         make_EOS_flag = false;
00103         Number_of_blocks_to_read = end_block_num - start_block_num +1;
00104     }
00105     
00106     
00107     for(buffer_112_counter=0;buffer_112_counter<112;buffer_112_counter++){
00108       
00109 
00110         if(new_session == true){          //check if it is beginnig of session  
00111 
00112             buffer_112[buffer_112_counter]=S_frame[counter_in_S_frame++];  // sending S frame 
00113             
00114             if(counter_in_S_frame==48){
00115 //                cout<<"new_session_over\n";
00116                 counter_in_S_frame=0;
00117                 new_session = false;
00118                 enable_T_frame = true;
00119 //              enable_SCH = true;
00120             }
00121         }
00122         else if(enable_T_frame == true){             // To send t frames
00123 
00124             if(block_counter != Number_of_blocks_to_read){                  
00125                 
00126                 if(first_block){                            // Read first block
00127 //                    cout<<"brooooooo"<<start_block_num<<"yo"<<endl;   
00128                          
00129                     disk_read(buffer_512,start_block_num );
00130                     counter_in_block = 0;
00131                     block_counter++;
00132                     
00133                     first_block = false;
00134 //                    cout<<"first block exit\n";
00135 //                   cout<<Number_of_blocks_to_read;
00136                    
00137                    //printf("\n");
00138 //                    for(int j=0;j<512;j++){
00139 //                    printf("%02X ",buffer_512[j]);
00140 //                    }
00141 //                    printf("\n");
00142 //                    if(block_counter == Number_of_blocks_to_read){
00143 //                        last_block = true;
00144 //                    }
00145                     
00146                     
00147                 }
00148                 if((counter_in_block == 318 )&&(sent_tm<38)){                 // Read next block
00149 
00150 //                    cout<<"next block exit\n";
00151                     disk_read(buffer_512,start_block_num + block_counter );
00152                     counter_in_block = 0;
00153                     block_counter++;
00154                     if(block_counter == Number_of_blocks_to_read){
00155                         last_block = true;
00156                     }
00157                 }
00158             }
00159                         
00160             if(!last_block){  
00161               
00162  //                 cout<<int(sent_tm)<<" ";
00163                 if(sent_tm<38){
00164                     buffer_112[buffer_112_counter] = buffer_512[counter_in_block++];    // sending T frames
00165 //                  cout<<int (counter_in_block)<<" ";
00166                     if(counter_in_block == 318){
00167                        
00168                         sent_tm = sent_tm + 2;
00169                     }   
00170                 }
00171                 else if(sent_tm == (T_frames-1)){
00172                     buffer_112[buffer_112_counter] = buffer_512[(counter_in_block++ )-159];
00173                     if(counter_in_block == 318){
00174 //                        cout<<"last block exit\n";
00175                         sent_tm = T_frames;
00176                     }
00177                 }
00178                 else if(sent_tm == T_frames){       // Give eos and start new session         
00179                     buffer_112[buffer_112_counter]=EoS[EOS_counter++];
00180                         if(EOS_counter == 120){
00181                             enable_T_frame = false;
00182                             new_session = true;
00183                             EOS_counter =0;
00184                             sent_tm=0;
00185                             repeat_T_frame = false;
00186 //                          cout<<"eos exit\n";
00187                         }
00188                 }
00189             }
00190             if(last_block){
00191 //                cout<<"lb";
00192                 if(sent_tm == (T_frames-1) && (repeat_T_frame == false)){
00193                     buffer_112[buffer_112_counter] = buffer_512[(counter_in_block++ )-159];
00194                     if(counter_in_block == 318){
00195 //                      cout<<"repeat block exit\n";
00196                         sent_tm = T_frames;
00197                     }
00198                 }
00199                  if((sent_tm == T_frames) && (repeat_T_frame == false)){       // Give eos and start new session         
00200                     buffer_112[buffer_112_counter]=EoS[EOS_counter++];
00201                        if(EOS_counter == 120){
00202 //                        cout<<"eos exit";
00203                         enable_T_frame = false;
00204                         new_session = true;
00205                         EOS_counter =0;
00206                         sent_tm=0;
00207                     }
00208                 }
00209                 else if((sent_tm < (T_frames-1)) && (repeat_T_frame == false)){
00210                     buffer_112[buffer_112_counter] = buffer_512[counter_in_block++];    // sending last two T frames    
00211                     if(counter_in_block == 318){
00212                         sent_tm = sent_tm + 2;
00213                         repeat_T_frame= true;
00214                     }
00215                 }
00216                 else if((sent_tm< T_frames) && (repeat_T_frame == true)){
00217                     buffer_112[buffer_112_counter] = buffer_512[(counter_in_block++ )-159];
00218                     if(counter_in_block == 477){
00219                         sent_tm = sent_tm +1;
00220                         counter_in_block = counter_in_block-159;
00221                     }
00222                 }
00223                 else if((sent_tm == T_frames ) && (repeat_T_frame == true)){       // Give eos and start new session         
00224                    
00225                     buffer_112[buffer_112_counter]=EoS[EOS_counter++];
00226                         if(EOS_counter == 120){
00227                         enable_T_frame = false;
00228                         new_session = true;
00229                         EOS_counter =0;
00230 //                    printf("yoooo %d",int(sent_tm));    
00231                         sent_tm=0;
00232                     
00233                         last_block = false;
00234                         last_buffer = true;
00235 //                        printf("i m here");
00236                         break;
00237                     }
00238                 }
00239                 
00240             }   
00241         
00242         }
00243                     
00244     }
00245     differential_encode(buffer_112, 112);
00246     if(last_buffer ==true){
00247     diff_prev=0;
00248     }
00249     
00250 }