Kyle McKeehan / Mbed 2 deprecated DataCommFRDM2

FRDM2

Dependencies:   mbed

main.cpp@0:906202f8e2f2, 2015-04-16 (annotated)

Committer:
n02655194
Date:
Thu Apr 16 14:13:01 2015 +0000
Revision:
0:906202f8e2f2
Child:
1:2bba0fcfda85
FRDM2

Who changed what in which revision?

UserRevisionLine numberNew contents of line
n02655194 0:906202f8e2f2 1 #include "mbed.h"
n02655194 0:906202f8e2f2 2 #include "stdio.h"
n02655194 0:906202f8e2f2 3 #include "C12832.h"
n02655194 0:906202f8e2f2 4
n02655194 0:906202f8e2f2 5 #define MAX 100 //set the size of the character data storage array
n02655194 0:906202f8e2f2 6 #define BYTE 8
n02655194 0:906202f8e2f2 7 #define NIBBLE 4 //used to set size of data read
n02655194 0:906202f8e2f2 8 #define PREAMBLE 0x7E //preamble of 01111110
n02655194 0:906202f8e2f2 9 #define POSTAMBLE 0x81 //postamble of 10000001
n02655194 0:906202f8e2f2 10 #define ADDRESS 0x11 //address of 00010010 - network of 1, id of 2.
n02655194 0:906202f8e2f2 11 #define NETWORK 0x10 //network portion of the address
n02655194 0:906202f8e2f2 12 #define ID 0x02 //id portion of the address
n02655194 0:906202f8e2f2 13 #define BROADCAST 0x00 //address of 00000000
n02655194 0:906202f8e2f2 14 //multicast using 4bit address / 4 bit network. network = 4 msb, address = 4 lsb. broadcast = all 0's. multicast = network id & address of 0's.
n02655194 0:906202f8e2f2 15 #define CRC 0x13 //crc of 10011 or x^4+x+1 or crc-5
n02655194 0:906202f8e2f2 16
n02655194 0:906202f8e2f2 17
n02655194 0:906202f8e2f2 18 C12832 lcd(p5, p7, p6, p8, p11); //LCD structure
n02655194 0:906202f8e2f2 19 DigitalOut myled(LED1), myled2(LED2), myled3(LED3), myled4(LED4); //variables to access the four blue leds
n02655194 0:906202f8e2f2 20 DigitalIn clock_pin(p21), serial_in(p22); //clock pulse input and data input pins
n02655194 0:906202f8e2f2 21 Timer t; //timer for pausing after postamble received before displaying data
n02655194 0:906202f8e2f2 22 unsigned char temp, data[MAX], crc_calc; //temp byte storage, storage array, transmitted crc value
n02655194 0:906202f8e2f2 23 unsigned char preamble, address, i, j, k; //increment variables
n02655194 0:906202f8e2f2 24 unsigned char data_flag, rflag, d_flag, done, temp_data; //data flags
n02655194 0:906202f8e2f2 25 int crc_passed = 0; //crc flag
n02655194 0:906202f8e2f2 26 int temp_crc = 0; //stores values for crc check.
n02655194 0:906202f8e2f2 27
n02655194 0:906202f8e2f2 28 //funtion prototypes
n02655194 0:906202f8e2f2 29 void check_byte(int value); //stays inside the function until the received byte matches the value passed into the function (PREAMBLE)
n02655194 0:906202f8e2f2 30 int check_abyte();//after preamble received checks the next byte for address. Returns 1 if address received matches ADDRESS, BROADCAST, or multicast; 0 if not.
n02655194 0:906202f8e2f2 31 int read_byte(int size); //reads received data and returns it a byte at a time.
n02655194 0:906202f8e2f2 32 int check_crc(int temp_crc, unsigned char crc_calc); //double checks the sent crc value - data sent without error.
n02655194 0:906202f8e2f2 33
n02655194 0:906202f8e2f2 34 //Improvements
n02655194 0:906202f8e2f2 35 //if crc correct display correct crc
n02655194 0:906202f8e2f2 36 //if crc correct send ACK(1) to Master
n02655194 0:906202f8e2f2 37 //if crc wrong, display incorrect crc
n02655194 0:906202f8e2f2 38 //if crc wrong, send NoACK(0) to Master
n02655194 0:906202f8e2f2 39 //if crc wrong adjust for retransmit
n02655194 0:906202f8e2f2 40
n02655194 0:906202f8e2f2 41
n02655194 0:906202f8e2f2 42 int main()
n02655194 0:906202f8e2f2 43 {
n02655194 0:906202f8e2f2 44
n02655194 0:906202f8e2f2 45 //turn off leds
n02655194 0:906202f8e2f2 46 myled = 0;
n02655194 0:906202f8e2f2 47 myled2 = 0;
n02655194 0:906202f8e2f2 48 myled3 = 0;
n02655194 0:906202f8e2f2 49 myled4 = 0;
n02655194 0:906202f8e2f2 50
n02655194 0:906202f8e2f2 51 //initialize variables
n02655194 0:906202f8e2f2 52 i = 0;
n02655194 0:906202f8e2f2 53 d_flag = 0;
n02655194 0:906202f8e2f2 54 done = 0;
n02655194 0:906202f8e2f2 55 crc_passed=0;
n02655194 0:906202f8e2f2 56
n02655194 0:906202f8e2f2 57
n02655194 0:906202f8e2f2 58 while(!d_flag)
n02655194 0:906202f8e2f2 59 {
n02655194 0:906202f8e2f2 60 //clear lcd screen, print current build message
n02655194 0:906202f8e2f2 61 lcd.cls();
n02655194 0:906202f8e2f2 62 lcd.locate(0,3);
n02655194 0:906202f8e2f2 63 lcd.printf("Waiting for Preamble");
n02655194 0:906202f8e2f2 64 //read input clock pulse and data checking for preamble.
n02655194 0:906202f8e2f2 65 //preamble while loop
n02655194 0:906202f8e2f2 66 check_byte(PREAMBLE);
n02655194 0:906202f8e2f2 67
n02655194 0:906202f8e2f2 68 //clear lcd screen, print current build message
n02655194 0:906202f8e2f2 69 lcd.cls();
n02655194 0:906202f8e2f2 70 lcd.locate(0,3);
n02655194 0:906202f8e2f2 71 lcd.printf("Preamble Received");
n02655194 0:906202f8e2f2 72
n02655194 0:906202f8e2f2 73 //preamble received check address (next byte), returns to preamble check if not addressed to station
n02655194 0:906202f8e2f2 74 if(check_abyte())
n02655194 0:906202f8e2f2 75 d_flag = 1;
n02655194 0:906202f8e2f2 76 }
n02655194 0:906202f8e2f2 77
n02655194 0:906202f8e2f2 78 while(!done)
n02655194 0:906202f8e2f2 79 {
n02655194 0:906202f8e2f2 80 //store data into character array if crc checks.
n02655194 0:906202f8e2f2 81 data[i] = 0; //initialize current array position to zero
n02655194 0:906202f8e2f2 82 temp_data = read_byte(BYTE); //store successfully transmitted data
n02655194 0:906202f8e2f2 83
n02655194 0:906202f8e2f2 84 //check for postamble
n02655194 0:906202f8e2f2 85 if(temp_data == POSTAMBLE)
n02655194 0:906202f8e2f2 86 {
n02655194 0:906202f8e2f2 87 //break out of while loop - data finished sending
n02655194 0:906202f8e2f2 88 done = 1;
n02655194 0:906202f8e2f2 89 //clear lcd screen, print current build message
n02655194 0:906202f8e2f2 90 lcd.cls();
n02655194 0:906202f8e2f2 91 lcd.locate(0,3);
n02655194 0:906202f8e2f2 92 lcd.printf("Postamble Received");
n02655194 0:906202f8e2f2 93 }
n02655194 0:906202f8e2f2 94
n02655194 0:906202f8e2f2 95 //store data in character array if not postamble - check crc when appropriate
n02655194 0:906202f8e2f2 96 else
n02655194 0:906202f8e2f2 97 {
n02655194 0:906202f8e2f2 98 data[i] = temp_data;
n02655194 0:906202f8e2f2 99 i++; //increment array position
n02655194 0:906202f8e2f2 100 //store the sent data into temp variable for crc calculation
n02655194 0:906202f8e2f2 101 temp_crc << 8;
n02655194 0:906202f8e2f2 102 temp_crc += temp_data;
n02655194 0:906202f8e2f2 103 //wait until i increments and then check to see if 3 bytes have been received
n02655194 0:906202f8e2f2 104 if( (i % 3) == 0)
n02655194 0:906202f8e2f2 105 {
n02655194 0:906202f8e2f2 106 //check crc
n02655194 0:906202f8e2f2 107 crc_calc = read_byte(NIBBLE);
n02655194 0:906202f8e2f2 108 if(check_crc(temp_crc, crc_calc))
n02655194 0:906202f8e2f2 109 {
n02655194 0:906202f8e2f2 110 crc_passed=1;
n02655194 0:906202f8e2f2 111 lcd.cls();
n02655194 0:906202f8e2f2 112 lcd.locate(0,3);
n02655194 0:906202f8e2f2 113 lcd.printf("Data passes CRC verification");
n02655194 0:906202f8e2f2 114 }else{
n02655194 0:906202f8e2f2 115 lcd.cls();
n02655194 0:906202f8e2f2 116 lcd.locate(0,3);
n02655194 0:906202f8e2f2 117 lcd.printf("Data fails CRC verification");
n02655194 0:906202f8e2f2 118 }
n02655194 0:906202f8e2f2 119 //zero out crc temp variable
n02655194 0:906202f8e2f2 120 temp_crc = 0;
n02655194 0:906202f8e2f2 121 }
n02655194 0:906202f8e2f2 122 }
n02655194 0:906202f8e2f2 123 }
n02655194 0:906202f8e2f2 124 //pause after displaying postamble received and then display data.
n02655194 0:906202f8e2f2 125 t.start();
n02655194 0:906202f8e2f2 126 //wait until the timer has reached the set time.
n02655194 0:906202f8e2f2 127 while(t.read_ms() < 1000)
n02655194 0:906202f8e2f2 128 {
n02655194 0:906202f8e2f2 129
n02655194 0:906202f8e2f2 130 }
n02655194 0:906202f8e2f2 131 //stop and reset the timer
n02655194 0:906202f8e2f2 132 t.stop();
n02655194 0:906202f8e2f2 133 t.reset();
n02655194 0:906202f8e2f2 134 if(crc_passed){//if crc passes display data, send ACK
n02655194 0:906202f8e2f2 135 //clear debugging messages - and reset lcd to original position before printing data.
n02655194 0:906202f8e2f2 136 //send ACK
n02655194 0:906202f8e2f2 137 lcd.cls();
n02655194 0:906202f8e2f2 138 lcd.locate(0,3);
n02655194 0:906202f8e2f2 139 lcd.printf("Received: ");
n02655194 0:906202f8e2f2 140 for(k=0; k<=i; k++)
n02655194 0:906202f8e2f2 141 lcd.printf("%c", data[k]);
n02655194 0:906202f8e2f2 142 }else{//if crc fails, send NOACK
n02655194 0:906202f8e2f2 143 //send NoACK
n02655194 0:906202f8e2f2 144 }
n02655194 0:906202f8e2f2 145 }
n02655194 0:906202f8e2f2 146
n02655194 0:906202f8e2f2 147 void check_byte(int value)
n02655194 0:906202f8e2f2 148 {
n02655194 0:906202f8e2f2 149 data_flag = 1;
n02655194 0:906202f8e2f2 150 temp = 0;
n02655194 0:906202f8e2f2 151 rflag=0;
n02655194 0:906202f8e2f2 152 //while loop
n02655194 0:906202f8e2f2 153 while(!rflag)
n02655194 0:906202f8e2f2 154 {
n02655194 0:906202f8e2f2 155 //read in data if clock is 1 and data flag is 1
n02655194 0:906202f8e2f2 156 if(clock_pin && data_flag)
n02655194 0:906202f8e2f2 157 {
n02655194 0:906202f8e2f2 158 //data is left shifted into our temporary variable.
n02655194 0:906202f8e2f2 159 //each new data bit is moved into the least significant bit after the rest of the bits are shifted to the left
n02655194 0:906202f8e2f2 160 //data must be sent from the other microcontroller shifted out from the most significant bit to the least significant bit.
n02655194 0:906202f8e2f2 161 temp = (temp << 1) + serial_in;
n02655194 0:906202f8e2f2 162 data_flag = 0;
n02655194 0:906202f8e2f2 163 if(temp == value)
n02655194 0:906202f8e2f2 164 rflag = 1;
n02655194 0:906202f8e2f2 165 }
n02655194 0:906202f8e2f2 166 //when clock returns to low - reset data flag to accept the next bit.
n02655194 0:906202f8e2f2 167 if(!clock_pin && !data_flag)
n02655194 0:906202f8e2f2 168 data_flag = 1;
n02655194 0:906202f8e2f2 169 }
n02655194 0:906202f8e2f2 170 }
n02655194 0:906202f8e2f2 171
n02655194 0:906202f8e2f2 172 int check_abyte()
n02655194 0:906202f8e2f2 173 {
n02655194 0:906202f8e2f2 174 j = 0;
n02655194 0:906202f8e2f2 175 temp = 0;
n02655194 0:906202f8e2f2 176 rflag=0;
n02655194 0:906202f8e2f2 177 //while loop
n02655194 0:906202f8e2f2 178 while(j<8)
n02655194 0:906202f8e2f2 179 {
n02655194 0:906202f8e2f2 180 //read in data if clock is 1 and data flag is 1
n02655194 0:906202f8e2f2 181 if(clock_pin && data_flag)
n02655194 0:906202f8e2f2 182 {
n02655194 0:906202f8e2f2 183 //data is left shifted into our temporary variable.
n02655194 0:906202f8e2f2 184 //each new data bit is moved into the least significant bit after the rest of the bits are shifted to the left
n02655194 0:906202f8e2f2 185 //data must be sent from the other microcontroller shifted out from the most significant bit to the least significant bit.
n02655194 0:906202f8e2f2 186 temp = (temp << 1) + serial_in;
n02655194 0:906202f8e2f2 187 j++;
n02655194 0:906202f8e2f2 188 data_flag = 0;
n02655194 0:906202f8e2f2 189 }
n02655194 0:906202f8e2f2 190 //when clock returns to low - reset data flag to accept the next bit.
n02655194 0:906202f8e2f2 191 if(!clock_pin && !data_flag)
n02655194 0:906202f8e2f2 192 data_flag = 1;
n02655194 0:906202f8e2f2 193 }
n02655194 0:906202f8e2f2 194
n02655194 0:906202f8e2f2 195 //clear lcd screen, print current build message
n02655194 0:906202f8e2f2 196 lcd.cls();
n02655194 0:906202f8e2f2 197 lcd.locate(0,3);
n02655194 0:906202f8e2f2 198 if(temp == ADDRESS)
n02655194 0:906202f8e2f2 199 {
n02655194 0:906202f8e2f2 200 rflag = 1;
n02655194 0:906202f8e2f2 201 lcd.printf("Address Received");
n02655194 0:906202f8e2f2 202 }
n02655194 0:906202f8e2f2 203 else if(temp == BROADCAST)
n02655194 0:906202f8e2f2 204 {
n02655194 0:906202f8e2f2 205 rflag = 1;
n02655194 0:906202f8e2f2 206 lcd.printf("Broadcast received");
n02655194 0:906202f8e2f2 207 }
n02655194 0:906202f8e2f2 208 else if(((temp & 0xF0) == NETWORK) && ((temp & 0x0F) == 0))
n02655194 0:906202f8e2f2 209 {
n02655194 0:906202f8e2f2 210 rflag = 1;
n02655194 0:906202f8e2f2 211 lcd.printf("Multicast received");
n02655194 0:906202f8e2f2 212 }//can add if Network==0 and address==x send to x in every network
n02655194 0:906202f8e2f2 213 else
n02655194 0:906202f8e2f2 214 printf("Wrong address received");
n02655194 0:906202f8e2f2 215
n02655194 0:906202f8e2f2 216 return rflag;
n02655194 0:906202f8e2f2 217 }
n02655194 0:906202f8e2f2 218
n02655194 0:906202f8e2f2 219 int read_byte(int size)
n02655194 0:906202f8e2f2 220 {
n02655194 0:906202f8e2f2 221 j = 0;
n02655194 0:906202f8e2f2 222 temp = 0;
n02655194 0:906202f8e2f2 223
n02655194 0:906202f8e2f2 224 //read a byte/nibble at a time and return it to main
n02655194 0:906202f8e2f2 225 while(j<size)
n02655194 0:906202f8e2f2 226 {
n02655194 0:906202f8e2f2 227 //read in data if clock is 1 and data flag is 1
n02655194 0:906202f8e2f2 228 if(clock_pin && data_flag) {
n02655194 0:906202f8e2f2 229 //data is left shifted into our temporary variable.
n02655194 0:906202f8e2f2 230 //each new data bit is moved into the least significant bit afater the rest of the bits are shifted to the left
n02655194 0:906202f8e2f2 231 //data must be sent from the other microcontroller shifted out from the most significant bit to the least significant bit.
n02655194 0:906202f8e2f2 232 temp = (temp << 1) + serial_in;
n02655194 0:906202f8e2f2 233 //increment j (tracks bits received) - turn off data_flag until clock changes.
n02655194 0:906202f8e2f2 234 j++;
n02655194 0:906202f8e2f2 235 data_flag = 0;
n02655194 0:906202f8e2f2 236 }
n02655194 0:906202f8e2f2 237 //when clock returns to low - reset data flag to accept the next bit.
n02655194 0:906202f8e2f2 238 if(!clock_pin && !data_flag)
n02655194 0:906202f8e2f2 239 data_flag = 1;
n02655194 0:906202f8e2f2 240 }
n02655194 0:906202f8e2f2 241 return temp;
n02655194 0:906202f8e2f2 242 }
n02655194 0:906202f8e2f2 243
n02655194 0:906202f8e2f2 244 int check_crc(int temp_crc, unsigned char crc_calc)
n02655194 0:906202f8e2f2 245 {
n02655194 0:906202f8e2f2 246 //assume data sent incorrectly, check crc to see if data sent correctly
n02655194 0:906202f8e2f2 247 int data_correct = 0;
n02655194 0:906202f8e2f2 248
n02655194 0:906202f8e2f2 249 //shift temp 3 bytes by 4 and add transmitted crc
n02655194 0:906202f8e2f2 250 temp_crc << 4;
n02655194 0:906202f8e2f2 251 temp_crc += crc_calc;
n02655194 0:906202f8e2f2 252 //check for crc correctness
n02655194 0:906202f8e2f2 253 if( (temp_crc % CRC) == 0)
n02655194 0:906202f8e2f2 254 data_correct = 1;
n02655194 0:906202f8e2f2 255
n02655194 0:906202f8e2f2 256 return data_correct;
n02655194 0:906202f8e2f2 257 }