iitm sat
/
CDMS_CODE_samp_23SEP_DMA
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Dependencies: FreescaleIAP SimpleDMA mbed-rtos mbed
Fork of
CDMS_CODE
by 
shubham c
Diff: SDCread.h
- Revision:
- 1:a0055b3280c8
- Child:
- 55:39e59903bc3a
- Child:
- 69:20f09a0c3fd2
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/SDCread.h Mon Dec 14 12:04:01 2015 +0000
@@ -0,0 +1,190 @@
+// It takes 276us to read from sd card and write in 112 buffer
+
+//~ #include"SDcard.h"
+#define T_frames 30
+unsigned char buffer_112_counter,sent_tm = 0;
+int disk_read(uint8_t *, uint64_t),j;
+bool new_session = true;
+bool last_buffer = false;
+bool first_block = true;
+bool last_block =false;
+bool repeat_T_frame = false;
+unsigned int counter_in_block=0,diff_prev=0;
+unsigned char EOS_counter = 0;
+unsigned char enable_T_frame = false;
+uint64_t start_block_num ; // Read from TC
+uint64_t end_block_num ; // Read from TC
+uint64_t Number_of_blocks_to_read ;
+uint64_t block_counter = 0;
+unsigned char buffer_512[512], buffer_112[112],counter_in_S_frame=0,counter_in_SCH=0;
+unsigned char make_EOS_flag = true;
+bool reset = false;
+
+void differential_encode(unsigned char* ptr, int length){
+
+ for(int i=0; i<length;i++){
+
+ unsigned char s = ptr[i] , t;
+ t = s ^ (s >> 1);
+ (diff_prev == 0) ? t=t^0x00 : t=t^0x80 ;
+ diff_prev = int(s & 0x01);
+ ptr[i] = t;
+ }
+
+ }
+
+void send_tm_from_SD_card(){
+
+ if(make_EOS_flag == true){
+ make_EOS_flag = false;
+ Number_of_blocks_to_read = end_block_num - start_block_num +1;
+ }
+
+
+ for(buffer_112_counter=0;buffer_112_counter<112;buffer_112_counter++){
+
+
+ if(new_session == true){ //check if it is beginnig of session
+
+ buffer_112[buffer_112_counter]=S_frame[counter_in_S_frame++]; // sending S frame
+
+ if(counter_in_S_frame==48){
+// cout<<"new_session_over\n";
+ counter_in_S_frame=0;
+ new_session = false;
+ enable_T_frame = true;
+// enable_SCH = true;
+ }
+ }
+ else if(enable_T_frame == true){ // To send t frames
+
+ if(block_counter != Number_of_blocks_to_read){
+
+ if(first_block){ // Read first block
+// cout<<"brooooooo"<<start_block_num<<"yo"<<endl;
+ SPI_mutex.lock();
+ disk_read(buffer_512,start_block_num );
+ SPI_mutex.unlock();
+ counter_in_block = 0;
+ block_counter++;
+
+ first_block = false;
+// cout<<"first block exit\n";
+// cout<<Number_of_blocks_to_read;
+
+ //printf("\n");
+// for(int j=0;j<512;j++){
+// printf("%02X ",buffer_512[j]);
+// }
+// printf("\n");
+// if(block_counter == Number_of_blocks_to_read){
+// last_block = true;
+// }
+
+
+ }
+ if((counter_in_block == 318 )&&(sent_tm<38)){ // Read next block
+
+// cout<<"next block exit\n";
+ SPI_mutex.lock();
+ disk_read(buffer_512,start_block_num + block_counter );
+ SPI_mutex.unlock();
+ counter_in_block = 0;
+ block_counter++;
+ if(block_counter == Number_of_blocks_to_read){
+ last_block = true;
+ }
+ }
+ }
+
+ if(!last_block){
+
+ // cout<<int(sent_tm)<<" ";
+ if(sent_tm<38){
+ buffer_112[buffer_112_counter] = buffer_512[counter_in_block++]; // sending T frames
+// cout<<int (counter_in_block)<<" ";
+ if(counter_in_block == 318){
+
+ sent_tm = sent_tm + 2;
+ }
+ }
+ else if(sent_tm == (T_frames-1)){
+ buffer_112[buffer_112_counter] = buffer_512[(counter_in_block++ )-159];
+ if(counter_in_block == 318){
+// cout<<"last block exit\n";
+ sent_tm = T_frames;
+ }
+ }
+ else if(sent_tm == T_frames){ // Give eos and start new session
+ buffer_112[buffer_112_counter]=EoS[EOS_counter++];
+ if(EOS_counter == 120){
+ enable_T_frame = false;
+ new_session = true;
+ EOS_counter =0;
+ sent_tm=0;
+ repeat_T_frame = false;
+// cout<<"eos exit\n";
+ }
+ }
+ }
+ if(last_block){
+// cout<<"lb";
+ if(sent_tm == (T_frames-1) && (repeat_T_frame == false)){
+ buffer_112[buffer_112_counter] = buffer_512[(counter_in_block++ )-159];
+ if(counter_in_block == 318){
+// cout<<"repeat block exit\n";
+ sent_tm = T_frames;
+ }
+ }
+ if((sent_tm == T_frames) && (repeat_T_frame == false)){ // Give eos and start new session
+ buffer_112[buffer_112_counter]=EoS[EOS_counter++];
+ if(EOS_counter == 120){
+// cout<<"eos exit";
+ enable_T_frame = false;
+ new_session = true;
+ EOS_counter =0;
+ sent_tm=0;
+ }
+ }
+ else if((sent_tm < (T_frames-1)) && (repeat_T_frame == false)){
+ buffer_112[buffer_112_counter] = buffer_512[counter_in_block++]; // sending last two T frames
+ if(counter_in_block == 318){
+ sent_tm = sent_tm + 2;
+ repeat_T_frame= true;
+ }
+ }
+ else if((sent_tm< T_frames) && (repeat_T_frame == true)){
+ buffer_112[buffer_112_counter] = buffer_512[(counter_in_block++ )-159];
+ if(counter_in_block == 477){
+ sent_tm = sent_tm +1;
+ counter_in_block = counter_in_block-159;
+ }
+ }
+ else if((sent_tm == T_frames ) && (repeat_T_frame == true)){ // Give eos and start new session
+
+ buffer_112[buffer_112_counter]=EoS[EOS_counter++];
+ if(EOS_counter == 120){
+ enable_T_frame = false;
+ new_session = true;
+ EOS_counter =0;
+// printf("yoooo %d",int(sent_tm));
+ sent_tm=0;
+
+ last_block = false;
+ last_buffer = true;
+ printf("?\r\n");
+ break;
+ }
+ }
+
+ }
+
+ }
+
+ }
+ differential_encode(buffer_112, 112);
+ if(last_buffer ==true){
+ diff_prev=0;
+ }
+
+}
\ No newline at end of file