Kevin Anderson / DataCommClassVersion

Serial communication protocol generic implementation

Dependents:   ClassFRDM ClassLPC

DataComm.cpp@0:60c4436f7667, 2015-03-19 (annotated)

Committer:
askksa12543
Date:
Thu Mar 19 02:36:11 2015 +0000
Revision:
0:60c4436f7667
Child:
1:9cfb17f74dcd
initial class version of data comm project.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
askksa12543 0:60c4436f7667 1 #include "DataComm.h"
askksa12543 0:60c4436f7667 2
askksa12543 0:60c4436f7667 3 void DataComm::setClockOut(PinName pin)
askksa12543 0:60c4436f7667 4 {
askksa12543 0:60c4436f7667 5 gpio_init_out_ex(&clock_out, pin, 0);
askksa12543 0:60c4436f7667 6 }
askksa12543 0:60c4436f7667 7
askksa12543 0:60c4436f7667 8 void DataComm::setClockIn(PinName pin)
askksa12543 0:60c4436f7667 9 {
askksa12543 0:60c4436f7667 10 gpio_init_in(&clock_in, pin);
askksa12543 0:60c4436f7667 11 }
askksa12543 0:60c4436f7667 12
askksa12543 0:60c4436f7667 13 void DataComm::setSerialOut(PinName pin)
askksa12543 0:60c4436f7667 14 {
askksa12543 0:60c4436f7667 15 gpio_init_out_ex(&serial_out, pin, 0);
askksa12543 0:60c4436f7667 16 }
askksa12543 0:60c4436f7667 17
askksa12543 0:60c4436f7667 18 void DataComm::setSerialIn(PinName pin)
askksa12543 0:60c4436f7667 19 {
askksa12543 0:60c4436f7667 20 gpio_init_in(&serial_in, pin);
askksa12543 0:60c4436f7667 21 }
askksa12543 0:60c4436f7667 22
askksa12543 0:60c4436f7667 23 void DataComm::listen()
askksa12543 0:60c4436f7667 24 {
askksa12543 0:60c4436f7667 25 int pre = 0, data_flag = 1;
askksa12543 0:60c4436f7667 26 char temp = 0;
askksa12543 0:60c4436f7667 27
askksa12543 0:60c4436f7667 28 while(!pre)
askksa12543 0:60c4436f7667 29 {
askksa12543 0:60c4436f7667 30 //read in data if clock is 1 and data flag is 1
askksa12543 0:60c4436f7667 31 if(gpio_read(&clock_in) && data_flag)
askksa12543 0:60c4436f7667 32 {
askksa12543 0:60c4436f7667 33 //data is left shifted into our temporary variable.
askksa12543 0:60c4436f7667 34 //each new data bit is moved into the least significant bit after the rest of the bits are shifted to the left
askksa12543 0:60c4436f7667 35 //data must be sent from the other microcontroller shifted out from the most significant bit to the least significant bit.
askksa12543 0:60c4436f7667 36 temp = (temp << 1) + gpio_read(&serial_in);
askksa12543 0:60c4436f7667 37 data_flag = 0;
askksa12543 0:60c4436f7667 38 if(temp == PREAMBLE)
askksa12543 0:60c4436f7667 39 {
askksa12543 0:60c4436f7667 40 pre = 1;
askksa12543 0:60c4436f7667 41 }
askksa12543 0:60c4436f7667 42 }
askksa12543 0:60c4436f7667 43 //when clock returns to low - reset data flag to accept the next bit.
askksa12543 0:60c4436f7667 44 if(!gpio_read(&clock_in) && !data_flag)
askksa12543 0:60c4436f7667 45 {
askksa12543 0:60c4436f7667 46 data_flag = 1;
askksa12543 0:60c4436f7667 47 }
askksa12543 0:60c4436f7667 48 }
askksa12543 0:60c4436f7667 49 }
askksa12543 0:60c4436f7667 50
askksa12543 0:60c4436f7667 51 void DataComm::setClock(int clock)
askksa12543 0:60c4436f7667 52 {
askksa12543 0:60c4436f7667 53 clock_time = clock;
askksa12543 0:60c4436f7667 54 skew_time = (clock * 9)/10;
askksa12543 0:60c4436f7667 55 }
askksa12543 0:60c4436f7667 56
askksa12543 0:60c4436f7667 57 void DataComm::initiate_connection()
askksa12543 0:60c4436f7667 58 {
askksa12543 0:60c4436f7667 59 int j=128, done=0, skew_flag=0;
askksa12543 0:60c4436f7667 60
askksa12543 0:60c4436f7667 61 //output preamble
askksa12543 0:60c4436f7667 62 while(!done)
askksa12543 0:60c4436f7667 63 {
askksa12543 0:60c4436f7667 64 //start timer for clock
askksa12543 0:60c4436f7667 65 t.start();
askksa12543 0:60c4436f7667 66 //wait until the timer has reached the set time.
askksa12543 0:60c4436f7667 67 while(t.read_ms() < clock_time)
askksa12543 0:60c4436f7667 68 {
askksa12543 0:60c4436f7667 69 //extract data just before clock goes high
askksa12543 0:60c4436f7667 70 if(!gpio_read(&clock_out) && skew_flag && t.read_ms() > skew_time)
askksa12543 0:60c4436f7667 71 {
askksa12543 0:60c4436f7667 72 //extract data bit
askksa12543 0:60c4436f7667 73 gpio_write(&serial_out, ((PREAMBLE / j) % 2));
askksa12543 0:60c4436f7667 74 skew_flag = 0;
askksa12543 0:60c4436f7667 75 j /= 2; //decrement j to get to next bit location
askksa12543 0:60c4436f7667 76 }
askksa12543 0:60c4436f7667 77 }
askksa12543 0:60c4436f7667 78 //stop and reset the timer
askksa12543 0:60c4436f7667 79 t.stop();
askksa12543 0:60c4436f7667 80 t.reset();
askksa12543 0:60c4436f7667 81 //switch clock signal
askksa12543 0:60c4436f7667 82 gpio_write(&clock_out, !gpio_read(&clock_out));
askksa12543 0:60c4436f7667 83 //reset skew flag
askksa12543 0:60c4436f7667 84 skew_flag = 1;
askksa12543 0:60c4436f7667 85 //last preamble bit sent - return from function
askksa12543 0:60c4436f7667 86 if(j==0)
askksa12543 0:60c4436f7667 87 {
askksa12543 0:60c4436f7667 88 done = 1;
askksa12543 0:60c4436f7667 89 }
askksa12543 0:60c4436f7667 90 }
askksa12543 0:60c4436f7667 91 }
askksa12543 0:60c4436f7667 92
askksa12543 0:60c4436f7667 93 void DataComm::setDataSize(int size)
askksa12543 0:60c4436f7667 94 {
askksa12543 0:60c4436f7667 95 data_size = size;
askksa12543 0:60c4436f7667 96 }
askksa12543 0:60c4436f7667 97
askksa12543 0:60c4436f7667 98 void DataComm::send_data(char data[])
askksa12543 0:60c4436f7667 99 {
askksa12543 0:60c4436f7667 100 int i=0, j=128, done=0, skew_flag=0;
askksa12543 0:60c4436f7667 101
askksa12543 0:60c4436f7667 102 //output data
askksa12543 0:60c4436f7667 103 while(!done)
askksa12543 0:60c4436f7667 104 {
askksa12543 0:60c4436f7667 105 //start timer for clock
askksa12543 0:60c4436f7667 106 t.start();
askksa12543 0:60c4436f7667 107 //wait until the timer has reached the set time.
askksa12543 0:60c4436f7667 108 while(t.read_ms() < clock_time)
askksa12543 0:60c4436f7667 109 {
askksa12543 0:60c4436f7667 110 //extract data just before clock goes high
askksa12543 0:60c4436f7667 111 if(!gpio_read(&clock_out) && skew_flag && t.read_ms() > skew_time)
askksa12543 0:60c4436f7667 112 {
askksa12543 0:60c4436f7667 113 //extract data bit
askksa12543 0:60c4436f7667 114 gpio_write(&serial_out, ((data[i] / j) % 2));
askksa12543 0:60c4436f7667 115 skew_flag = 0;
askksa12543 0:60c4436f7667 116 j /= 2; //decrement j to get to next bit location
askksa12543 0:60c4436f7667 117 }
askksa12543 0:60c4436f7667 118 }
askksa12543 0:60c4436f7667 119 //stop and reset the timer
askksa12543 0:60c4436f7667 120 t.stop();
askksa12543 0:60c4436f7667 121 t.reset();
askksa12543 0:60c4436f7667 122 //switch clock signal
askksa12543 0:60c4436f7667 123 gpio_write(&clock_out, !gpio_read(&clock_out));
askksa12543 0:60c4436f7667 124 //reset skew flag
askksa12543 0:60c4436f7667 125 skew_flag = 1;
askksa12543 0:60c4436f7667 126 //last preamble bit sent - return from function
askksa12543 0:60c4436f7667 127 if(j==0)
askksa12543 0:60c4436f7667 128 {
askksa12543 0:60c4436f7667 129 i++;
askksa12543 0:60c4436f7667 130 if(i>data_size)
askksa12543 0:60c4436f7667 131 done = 1;
askksa12543 0:60c4436f7667 132 j=128;
askksa12543 0:60c4436f7667 133 }
askksa12543 0:60c4436f7667 134 }
askksa12543 0:60c4436f7667 135 }
askksa12543 0:60c4436f7667 136
askksa12543 0:60c4436f7667 137 char* DataComm::receive_data()
askksa12543 0:60c4436f7667 138 {
askksa12543 0:60c4436f7667 139 int i=0, j=0, done = 0, data_flag = 1;
askksa12543 0:60c4436f7667 140 char temp[data_size];
askksa12543 0:60c4436f7667 141
askksa12543 0:60c4436f7667 142 while(!done)
askksa12543 0:60c4436f7667 143 {
askksa12543 0:60c4436f7667 144 //read in data if clock is 1 and data flag is 1
askksa12543 0:60c4436f7667 145 if(gpio_read(&clock_in) && data_flag)
askksa12543 0:60c4436f7667 146 {
askksa12543 0:60c4436f7667 147 //data is left shifted into our temporary variable.
askksa12543 0:60c4436f7667 148 //each new data bit is moved into the least significant bit after the rest of the bits are shifted to the left
askksa12543 0:60c4436f7667 149 //data must be sent from the other microcontroller shifted out from the most significant bit to the least significant bit.
askksa12543 0:60c4436f7667 150 temp[i] = (temp[i] << 1) + gpio_read(&serial_in);
askksa12543 0:60c4436f7667 151 data_flag = 0;
askksa12543 0:60c4436f7667 152 j++;
askksa12543 0:60c4436f7667 153 }
askksa12543 0:60c4436f7667 154 //when clock returns to low - reset data flag to accept the next bit.
askksa12543 0:60c4436f7667 155 if(!gpio_read(&clock_in) && !data_flag)
askksa12543 0:60c4436f7667 156 {
askksa12543 0:60c4436f7667 157 data_flag = 1;
askksa12543 0:60c4436f7667 158 }
askksa12543 0:60c4436f7667 159 if(j>7)
askksa12543 0:60c4436f7667 160 {
askksa12543 0:60c4436f7667 161 i++;
askksa12543 0:60c4436f7667 162 if(i>data_size)
askksa12543 0:60c4436f7667 163 done=1;
askksa12543 0:60c4436f7667 164 j=0;
askksa12543 0:60c4436f7667 165 }
askksa12543 0:60c4436f7667 166 }
askksa12543 0:60c4436f7667 167 return temp;
askksa12543 0:60c4436f7667 168 }