nikita teggi / Mbed 2 deprecated merged_code2_3rd_nov_2017

Changes done in ECG and BT

Dependencies:   SDFileSystem ds3231 eeprom_Nikita mbed testUniGraphic_150217

Fork of merged_code2_20sept_2017_4th_oct_2017 by nikita teggi

ecgg.cpp@20:7c64e6ecad76, 2017-06-17 (annotated)

Committer:
nikitateggi
Date:
Sat Jun 17 09:36:18 2017 +0000
Revision:
20:7c64e6ecad76
Parent:
19:1650bbc923cc
Child:
22:ffa88619551d
poc code with finger detect and leadoff

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nikitateggi 1:8316c23ec6b9 1 /** ECG ADS1291 Test program.
nikitateggi 1:8316c23ec6b9 2 ADS1291 is a single channel ECG chip
nikitateggi 1:8316c23ec6b9 3 with a 24 bit Sigma-Delta ADC
nikitateggi 1:8316c23ec6b9 4 */
nikitateggi 1:8316c23ec6b9 5
nikitateggi 1:8316c23ec6b9 6 #include "mbed.h"
nikitateggi 1:8316c23ec6b9 7 #include <string.h>
nikitateggi 1:8316c23ec6b9 8 #include <stdio.h>
nikitateggi 1:8316c23ec6b9 9 #include "ds3231.h"
nikitateggi 1:8316c23ec6b9 10 #include "SDFileSystem.h"
nikitateggi 1:8316c23ec6b9 11 #include "ecg_dec.h"
nikitateggi 1:8316c23ec6b9 12 #include "rtc.h"
nikitateggi 1:8316c23ec6b9 13 #include "sdcard.h"
nikitateggi 3:9a06c2bed650 14 #include "ec_bp.h"
nidhinvarghese 14:f5c62d30c6fc 15
nidhinvarghese 14:f5c62d30c6fc 16 #include "struct.h" // Added on 31/5/17_Nidhin
nikitateggi 19:1650bbc923cc 17 //#include "test_type.h" //Added on 31/5/17_Nidhin
nikitateggi 3:9a06c2bed650 18 Serial pc(USBTX,USBRX);
nikitateggi 1:8316c23ec6b9 19
nikitateggi 1:8316c23ec6b9 20
nikitateggi 1:8316c23ec6b9 21
suhasini 13:5d3b478ea9c7 22 float ecg(int pid)
nikitateggi 3:9a06c2bed650 23 {
nikitateggi 20:7c64e6ecad76 24
nikitateggi 20:7c64e6ecad76 25 uint8_t lead_reg=0; // added on 14/06 to check lead -off
nidhinvarghese 14:f5c62d30c6fc 26 //----------------------- Structure for Bluetooth Added Nidhin 1/6/2017-------------------//
nidhinvarghese 14:f5c62d30c6fc 27
nidhinvarghese 14:f5c62d30c6fc 28 //BLUETOOTH STRUCTURE
nidhinvarghese 14:f5c62d30c6fc 29
nidhinvarghese 14:f5c62d30c6fc 30 BLEMsg_info *ptr_BLEMsg_info_ecg, BLEMsg_info_ecg; // A copy of master strcuture [ "BLEMsg_info" ] by name "BLEMsg_info_ecg" is created
nidhinvarghese 14:f5c62d30c6fc 31 ptr_BLEMsg_info_ecg = &BLEMsg_info_ecg; // *ptr_BLEMsg_info_bp is the pointer to local copy;
nidhinvarghese 14:f5c62d30c6fc 32
nidhinvarghese 14:f5c62d30c6fc 33 // Declaration of Date Structure
nidhinvarghese 14:f5c62d30c6fc 34 DateTime_info *ptr_DateTime_info_ecg, DateTime_info_ecg; // A copy of Master Structure "DateTime_info" created,
nidhinvarghese 14:f5c62d30c6fc 35 ptr_DateTime_info_ecg = &DateTime_info_ecg; // Structure pointer points to that copy.
nidhinvarghese 14:f5c62d30c6fc 36
nidhinvarghese 14:f5c62d30c6fc 37
nidhinvarghese 14:f5c62d30c6fc 38 // RTC operations
nidhinvarghese 14:f5c62d30c6fc 39 time_t epoch_time_ecg; //A copy of time_t by name epoch_time_bp is created
nidhinvarghese 14:f5c62d30c6fc 40 epoch_time_ecg = rtc_read(); // time is got from get epoch function.
nidhinvarghese 14:f5c62d30c6fc 41
nidhinvarghese 14:f5c62d30c6fc 42 struct tm * ptr_time_info_ecg, time_info_ecg; // Sturucture copy of tm is created
nidhinvarghese 14:f5c62d30c6fc 43 ptr_time_info_ecg = localtime(&epoch_time_ecg); // Structure accepts the time in local format from "time_t" type.
nidhinvarghese 14:f5c62d30c6fc 44
nidhinvarghese 14:f5c62d30c6fc 45 //BELOW LINE IS TO CHECK Date and TIME
nidhinvarghese 15:208b146151ba 46 //pc.printf("Time is %d: %d: %d\n", (*ptr_time_info_ecg).tm_hour, (*ptr_time_info_ecg).tm_min, (*ptr_time_info_ecg).tm_sec);
nidhinvarghese 15:208b146151ba 47 //pc.printf("Date is %d:%d:%d\n", (*ptr_time_info_ecg).tm_mday, (*ptr_time_info_ecg).tm_mon+1, (*ptr_time_info_ecg).tm_year-100);
nidhinvarghese 14:f5c62d30c6fc 48
nidhinvarghese 14:f5c62d30c6fc 49 //Copying from one structure to the other using variables
nidhinvarghese 14:f5c62d30c6fc 50 DateTime_info_ecg.hour = (uint8_t)(*ptr_time_info_ecg).tm_hour;
nidhinvarghese 14:f5c62d30c6fc 51 DateTime_info_ecg.mins = (uint8_t)(*ptr_time_info_ecg).tm_min;
nidhinvarghese 14:f5c62d30c6fc 52 DateTime_info_ecg.sec = (uint8_t)(*ptr_time_info_ecg).tm_sec;
nidhinvarghese 14:f5c62d30c6fc 53
nidhinvarghese 14:f5c62d30c6fc 54 DateTime_info_ecg.date = (uint8_t) (*ptr_time_info_ecg).tm_mday;
nidhinvarghese 14:f5c62d30c6fc 55 DateTime_info_ecg.month =(uint8_t)(*ptr_time_info_ecg).tm_mon+1;
nidhinvarghese 14:f5c62d30c6fc 56 DateTime_info_ecg.year = (uint8_t)(*ptr_time_info_ecg).tm_year-100;
nidhinvarghese 14:f5c62d30c6fc 57
nidhinvarghese 14:f5c62d30c6fc 58 // Copying Time to Main structure
nidhinvarghese 14:f5c62d30c6fc 59 BLEMsg_info_ecg.date_time.hour = DateTime_info_ecg.hour;
nidhinvarghese 14:f5c62d30c6fc 60 BLEMsg_info_ecg.date_time.mins = DateTime_info_ecg.mins;
nidhinvarghese 14:f5c62d30c6fc 61 BLEMsg_info_ecg.date_time.sec = DateTime_info_ecg.sec;
nidhinvarghese 14:f5c62d30c6fc 62
nidhinvarghese 14:f5c62d30c6fc 63 BLEMsg_info_ecg.date_time.date = DateTime_info_ecg.date ;
nidhinvarghese 14:f5c62d30c6fc 64 BLEMsg_info_ecg.date_time.month = DateTime_info_ecg.month ;
nidhinvarghese 14:f5c62d30c6fc 65 BLEMsg_info_ecg.date_time.year = DateTime_info_ecg.year ;
nidhinvarghese 14:f5c62d30c6fc 66
nidhinvarghese 14:f5c62d30c6fc 67
nidhinvarghese 14:f5c62d30c6fc 68 //Checking if the structure has these values
nidhinvarghese 15:208b146151ba 69 //pc.printf("Time 2 is %d:%d:%d\n", DateTime_info_ecg.hour, DateTime_info_ecg.mins, DateTime_info_ecg.sec);
nidhinvarghese 15:208b146151ba 70 //pc.printf("\t Date is %d:%d:%d\n",DateTime_info_ecg.date, DateTime_info_ecg.month, DateTime_info_ecg.year);
nidhinvarghese 14:f5c62d30c6fc 71
nidhinvarghese 14:f5c62d30c6fc 72
nidhinvarghese 14:f5c62d30c6fc 73 //Loading values to of Test type
nidhinvarghese 14:f5c62d30c6fc 74 test_type_info test_type_info_ecg; // copy of " test_type_info" created
nidhinvarghese 14:f5c62d30c6fc 75 test_type_info_ecg = ECG_Test; // Loaded value 00 to the test type
nidhinvarghese 14:f5c62d30c6fc 76
nidhinvarghese 14:f5c62d30c6fc 77 BLEMsg_info_ecg.test_type = test_type_info_ecg;
nidhinvarghese 14:f5c62d30c6fc 78 //Check if 00 is getting printed
nidhinvarghese 15:208b146151ba 79 //pc.printf("Test Type is : %d\n", test_type_info_ecg);
nidhinvarghese 14:f5c62d30c6fc 80
nidhinvarghese 14:f5c62d30c6fc 81
nidhinvarghese 14:f5c62d30c6fc 82 // Loading values of Length , PID, DID, sampling frequency, number of samples, calculated data.
nidhinvarghese 14:f5c62d30c6fc 83 BLEMsg_info_ecg.device_id = 01; // Device ID fixed
nidhinvarghese 14:f5c62d30c6fc 84 BLEMsg_info_ecg.patient_id = (uint32_t)pid; // Patient ID
nidhinvarghese 14:f5c62d30c6fc 85 BLEMsg_info_ecg.sampling_freq = 500; // sampling frrquency
nidhinvarghese 14:f5c62d30c6fc 86 BLEMsg_info_ecg.length = 4026; //Total length of data in bytes 22 B+10752 B
nidhinvarghese 14:f5c62d30c6fc 87
nidhinvarghese 14:f5c62d30c6fc 88 /*
nidhinvarghese 14:f5c62d30c6fc 89 //Loading number of samples
nidhinvarghese 14:f5c62d30c6fc 90 NumSamples_info NumSamples_info_bp; //Copy of structure NumSamples_info
nidhinvarghese 14:f5c62d30c6fc 91 NumSamples_info_bp.num_ppg_sample = 1664; // PPG & ECG Sample number loaded in structure copy
nidhinvarghese 14:f5c62d30c6fc 92 NumSamples_info_bp.num_ecg_sample = 1024;
nidhinvarghese 14:f5c62d30c6fc 93 */
nidhinvarghese 14:f5c62d30c6fc 94
nidhinvarghese 14:f5c62d30c6fc 95 BLEMsg_info_ecg.num_samples.num_sample_ppg_dummy = 0 ;// PPG number of samples copied to master struct
nidhinvarghese 14:f5c62d30c6fc 96 BLEMsg_info_ecg.num_samples.num_sample_ecg_OTtyp = 1000 ; // ECG number of samples copied to master struct
nidhinvarghese 14:f5c62d30c6fc 97
nidhinvarghese 14:f5c62d30c6fc 98 //----------------------------------------END Structure for Bluetooth - Added Nidhin 1/6/2017-------
nidhinvarghese 14:f5c62d30c6fc 99
nidhinvarghese 14:f5c62d30c6fc 100
nikitateggi 1:8316c23ec6b9 101
nidhinvarghese 15:208b146151ba 102 int32_t concatenate_value2 = 0; // ORG. "int concatenate_value2 = 0;" Nidhin 1/6/17
nidhinvarghese 15:208b146151ba 103 int32_t *ecg_ptr; // Added 1/6/2017 Nidhin
nidhinvarghese 14:f5c62d30c6fc 104 ecg_ptr = &concatenate_value2; // Pointer to pass for ECG write into SD card Nidhin 1/6/2017
nidhinvarghese 14:f5c62d30c6fc 105
suhasini 13:5d3b478ea9c7 106 // int32_t sample_sum; // static int32_t avg[1500];
suhasini 13:5d3b478ea9c7 107 int32_t count = 0; int32_t fs = 500;
nidhinvarghese 17:22a87e12fb3a 108 uint32_t ecg_buf[N_ECG]; // Moved out of func() Nidhin 9/6/17
nikitateggi 3:9a06c2bed650 109 Timer t;
suhasini 13:5d3b478ea9c7 110
suhasini 13:5d3b478ea9c7 111 //------------------ Declaration for Peak value detection ------------------------------------
suhasini 13:5d3b478ea9c7 112
suhasini 13:5d3b478ea9c7 113 uint32_t hi_val;uint32_t pk_val[20];unsigned int pk_pos[20]={0};unsigned int a; //uint32_t pk=0;
suhasini 13:5d3b478ea9c7 114 int hi_dif = 0;int j=0; // int count1 = N_ECG/fs, a_dif=0, fs1 = fs ,h=0;
suhasini 13:5d3b478ea9c7 115 // ------------------------- Declaration for Heart Rate calculation --------------------------
suhasini 13:5d3b478ea9c7 116 int n=0; //int n=10;
suhasini 13:5d3b478ea9c7 117 float pos_dif, HR[2], HR1,t_pos_dif;int t_sec = 60; float HR_sum = 0,HR_avg;
suhasini 13:5d3b478ea9c7 118 // -------------------------------------------------------------------------------------------
suhasini 13:5d3b478ea9c7 119
suhasini 13:5d3b478ea9c7 120 // unsigned char chk = 1;
nikitateggi 3:9a06c2bed650 121 pc.baud(baud_rate);
nikitateggi 4:6bd81bb1790d 122 freqset(); // setting the frequency
nikitateggi 4:6bd81bb1790d 123 setupfunc();
nikitateggi 20:7c64e6ecad76 124 lead_reg=ecgsetupfunc(); // added a return function to read leadoff // 14/06
suhasini 13:5d3b478ea9c7 125 // chk = 1;
nikitateggi 20:7c64e6ecad76 126 if (lead_reg==0) // checking for proper lead contact// 14/06
nikitateggi 20:7c64e6ecad76 127 {
nidhinvarghese 14:f5c62d30c6fc 128 //ORIGINAL sd_open_ECGfile(pid); // opening the ecg file COMMENTED Nidhin 1/6/2017
nidhinvarghese 14:f5c62d30c6fc 129 sd_open_ECGfilee(pid); // REPLACED Nidhin 1/6/2017 Nidhin
nidhinvarghese 14:f5c62d30c6fc 130
suhasini 13:5d3b478ea9c7 131 pc.printf( "Raw data is = \n");
nikitateggi 3:9a06c2bed650 132 for(int i=0; i<N_ECG; i++)
nikitateggi 3:9a06c2bed650 133 {
nikitateggi 3:9a06c2bed650 134 concatenate_value2= readvalue();
nidhinvarghese 14:f5c62d30c6fc 135
nidhinvarghese 14:f5c62d30c6fc 136 //ORIGINAL sd_write(concatenate_value2); // writing into the sd card COMMENTED Nidhin 1/6/2017
nidhinvarghese 14:f5c62d30c6fc 137 sd_ecgwrite(ecg_ptr); // REPLACED Nidhin 1/6/2017
nidhinvarghese 14:f5c62d30c6fc 138
suhasini 13:5d3b478ea9c7 139 ecg_buf[i] = concatenate_value2;
nikitateggi 20:7c64e6ecad76 140 //// pc.printf( "%d\n", concatenate_value2); //COMMENTED Nidhin 1/6/2017
nikitateggi 3:9a06c2bed650 141 }
nidhinvarghese 14:f5c62d30c6fc 142
nidhinvarghese 14:f5c62d30c6fc 143 //sd_close(); // closing the file COMMENTED Nidhin 1/6/2017
nidhinvarghese 14:f5c62d30c6fc 144 sd_close_ecg(); // closing the ECG file REPLACED Nidhin 1/6/2017 Nidhin
suhasini 13:5d3b478ea9c7 145 /*
suhasini 13:5d3b478ea9c7 146 // ---------- reading back SD data for processing --------------------
suhasini 13:5d3b478ea9c7 147 sd_read_file(15);
suhasini 13:5d3b478ea9c7 148 printf("Reading back SD data\n");
suhasini 13:5d3b478ea9c7 149 for(int i=10;i<N_ECG;i++)
suhasini 13:5d3b478ea9c7 150 {
suhasini 13:5d3b478ea9c7 151 ecg_buf= sd_read();
suhasini 13:5d3b478ea9c7 152 //printf("%d\n",ecg_buf[i]);
suhasini 13:5d3b478ea9c7 153 }
suhasini 13:5d3b478ea9c7 154
suhasini 13:5d3b478ea9c7 155 sd_close(); */
suhasini 13:5d3b478ea9c7 156
suhasini 13:5d3b478ea9c7 157 //----------------------------- PEAK DETECTION AND HEART RATE CALCULATION ---------------------------------------------------
suhasini 13:5d3b478ea9c7 158 // -------------------------------------- PEAK DETECTION -------------------------------------------------------------
suhasini 13:5d3b478ea9c7 159
suhasini 13:5d3b478ea9c7 160 // ------------------ Main loop ---------------------------------
nikitateggi 3:9a06c2bed650 161
suhasini 13:5d3b478ea9c7 162 for(int i=0;i<N_ECG-10;i++){
suhasini 13:5d3b478ea9c7 163 if(ecg_buf[i]>ecg_buf[i+1])
suhasini 13:5d3b478ea9c7 164 {
suhasini 13:5d3b478ea9c7 165 hi_val = ecg_buf[i]; //To find the high value
suhasini 13:5d3b478ea9c7 166 //printf("high value= %d\n",hi_val);
suhasini 13:5d3b478ea9c7 167 a = i;
suhasini 13:5d3b478ea9c7 168 //printf("a= %d\n",a);
suhasini 13:5d3b478ea9c7 169 hi_dif = hi_val-ecg_buf[a+10];
suhasini 13:5d3b478ea9c7 170
suhasini 13:5d3b478ea9c7 171 //a_dif = ecg_buf[a+2] - ecg_buf[a+1];
suhasini 13:5d3b478ea9c7 172 //printf("The difference between high and low value is = %d\n",hi_dif);
suhasini 13:5d3b478ea9c7 173
suhasini 13:5d3b478ea9c7 174 // ---------------------------- If hi_val is greater than next ten input values, then compare the hi_val with the tenth input value.
suhasini 13:5d3b478ea9c7 175 // If the diff is greater than 10000, then it is a valid peak (pls chk the below condition)--------------------------------------------------
suhasini 13:5d3b478ea9c7 176 // if((hi_dif > 10000) && ((a+10) < N_ECG))
suhasini 13:5d3b478ea9c7 177 if(hi_dif > 10000)
suhasini 13:5d3b478ea9c7 178 {
suhasini 13:5d3b478ea9c7 179 // if(a_dif <= 0) ------------------------ add this condition if needed ----------------------
suhasini 13:5d3b478ea9c7 180 // {
suhasini 13:5d3b478ea9c7 181 pk_val[j] = hi_val; //if condition satisfied, put the "pk" value into "pk_val" buffer
nikitateggi 20:7c64e6ecad76 182 //// pc.printf("peak value= %d\n",pk_val[j]);
suhasini 13:5d3b478ea9c7 183 pk_pos[j]=a; // also save the peak's position
nikitateggi 20:7c64e6ecad76 184 //// pc.printf("peak position is = %d\n",pk_pos[j]);
suhasini 13:5d3b478ea9c7 185 i = a+120; // once confirmed that this is the necessary peak, skip the next 120 input values
suhasini 13:5d3b478ea9c7 186 n = j; // where n is the number of peaks detected
suhasini 13:5d3b478ea9c7 187 j = j+1;
suhasini 13:5d3b478ea9c7 188
suhasini 13:5d3b478ea9c7 189 // printf("j after peak detection is= %d\n",j);
suhasini 13:5d3b478ea9c7 190 // }
suhasini 13:5d3b478ea9c7 191 }
suhasini 13:5d3b478ea9c7 192 else
suhasini 13:5d3b478ea9c7 193 {
suhasini 13:5d3b478ea9c7 194 //h = a+1;
suhasini 13:5d3b478ea9c7 195 i = a+1;
suhasini 13:5d3b478ea9c7 196 // printf("i if peak not found is= %d\n",i);
suhasini 13:5d3b478ea9c7 197 }
suhasini 13:5d3b478ea9c7 198 // store the peak value position in "pk_pos"
suhasini 13:5d3b478ea9c7 199
suhasini 13:5d3b478ea9c7 200 }
suhasini 13:5d3b478ea9c7 201 }
suhasini 13:5d3b478ea9c7 202 // ----------------- HEART RATE LOGIC ---------------------------
nikitateggi 3:9a06c2bed650 203
suhasini 13:5d3b478ea9c7 204 for(int i = 0;i < n-1;i++)
suhasini 13:5d3b478ea9c7 205 {
suhasini 13:5d3b478ea9c7 206 pos_dif = pk_pos[i+1] - pk_pos[i]; // difference between two consequtive peaks
suhasini 13:5d3b478ea9c7 207 pc.printf("peak position diff is = %f\n",pos_dif);
suhasini 13:5d3b478ea9c7 208 //printf("peak position i value is = %d\n",i);
suhasini 13:5d3b478ea9c7 209 t_pos_dif = pos_dif/fs; // sample difference between peak positions divided by sampling frequency gives the difference value in terms of actual time
suhasini 13:5d3b478ea9c7 210 pc.printf("time in seconds is = %f\n",t_pos_dif);
suhasini 13:5d3b478ea9c7 211 HR[i] = t_sec/t_pos_dif; //HR calculation
suhasini 13:5d3b478ea9c7 212 pc.printf("Heart Rate is = %f\n",HR[i]);
suhasini 13:5d3b478ea9c7 213 // n = i;
suhasini 13:5d3b478ea9c7 214 HR1 = HR[0];
suhasini 13:5d3b478ea9c7 215
suhasini 13:5d3b478ea9c7 216 }
suhasini 13:5d3b478ea9c7 217 // ---------------------- To average individual HRs for higher number of samples -----------------------
suhasini 13:5d3b478ea9c7 218 /* for(int i = 0;i < 5;i++)
suhasini 13:5d3b478ea9c7 219 {
suhasini 13:5d3b478ea9c7 220 HR_sum = HR[i]+HR_sum;
suhasini 13:5d3b478ea9c7 221 }
suhasini 13:5d3b478ea9c7 222 HR_avg = HR_sum/5; // To find average of all the individual HRs calculated
suhasini 13:5d3b478ea9c7 223 printf("Heart Rate sum is = %f\n",HR_sum);
suhasini 13:5d3b478ea9c7 224 printf("Denominator = %d\n",n);
suhasini 13:5d3b478ea9c7 225 printf("Heart Rate = %f\n",HR_avg);
suhasini 13:5d3b478ea9c7 226 */
nidhinvarghese 14:f5c62d30c6fc 227
nidhinvarghese 14:f5c62d30c6fc 228 //ADDED Nidhin 1/6/2017
nidhinvarghese 14:f5c62d30c6fc 229
nidhinvarghese 14:f5c62d30c6fc 230 BLEMsg_info_ecg.cal_data.cal_sbp_dummy = 0;
nidhinvarghese 14:f5c62d30c6fc 231 BLEMsg_info_ecg.cal_data.cal_dbp_OTtyp = (uint16_t)HR1; //To be modified after HR code is added.
nidhinvarghese 14:f5c62d30c6fc 232
nidhinvarghese 14:f5c62d30c6fc 233 structure_file(ptr_BLEMsg_info_ecg, pid); //copy the ECG structure to Main file
nidhinvarghese 14:f5c62d30c6fc 234 ecgfile_mainfile(pid); // copy raw data to the main file and ECG file is cleared.
nidhinvarghese 14:f5c62d30c6fc 235
nidhinvarghese 14:f5c62d30c6fc 236 pc.printf("Closed the main file\n");
nidhinvarghese 14:f5c62d30c6fc 237
nidhinvarghese 14:f5c62d30c6fc 238
nidhinvarghese 14:f5c62d30c6fc 239
suhasini 13:5d3b478ea9c7 240 return HR1;
suhasini 13:5d3b478ea9c7 241 // return HR_avg;
nikitateggi 20:7c64e6ecad76 242 }
nikitateggi 20:7c64e6ecad76 243
nikitateggi 20:7c64e6ecad76 244 else
nikitateggi 20:7c64e6ecad76 245 {
nikitateggi 20:7c64e6ecad76 246 pc.printf("no - leadoff");
nikitateggi 20:7c64e6ecad76 247 return 0;
nikitateggi 20:7c64e6ecad76 248 }
suhasini 13:5d3b478ea9c7 249
suhasini 13:5d3b478ea9c7 250 } // End of main function
suhasini 13:5d3b478ea9c7 251