Kevin Anderson / Mbed 2 deprecated DataCommFreedom

Using FRDM Board to output data and a clock for communications example.

Dependencies:   mbed

main.cpp@2:11f32d8cfa11, 2015-03-15 (annotated)

Committer:
askksa12543
Date:
Sun Mar 15 03:02:48 2015 +0000
Revision:
2:11f32d8cfa11
Parent:
1:4c0c28cc2b2c
Child:
3:027d30718bbc
corrected send/receive for multi bytes

Who changed what in which revision?

UserRevisionLine numberNew contents of line
askksa12543 2:11f32d8cfa11 1 //project to include preamble, addressing, control, error control.
askksa12543 2:11f32d8cfa11 2 //currently fixed size data field but doesn't have to be. (post amble if not fixed size)
askksa12543 2:11f32d8cfa11 3
askksa12543 0:7c7f4b30d64f 4 #include "mbed.h"
askksa12543 0:7c7f4b30d64f 5 #include "stdio.h"
askksa12543 0:7c7f4b30d64f 6
askksa12543 2:11f32d8cfa11 7 #define MAX 100 //set the size of the character data storage array
askksa12543 2:11f32d8cfa11 8
askksa12543 2:11f32d8cfa11 9 DigitalOut myled(LED1); // red led on board
askksa12543 2:11f32d8cfa11 10 DigitalOut clock_pin(D8), serial_out(D7); //send clock pulse and tx
askksa12543 0:7c7f4b30d64f 11 Timer t; //timer for controlling the clock and data skew
askksa12543 2:11f32d8cfa11 12 int msecs, sksecs; //clock time needed for data transfer and skew time
askksa12543 0:7c7f4b30d64f 13 int skew_flag; //skew flag for while loop
askksa12543 2:11f32d8cfa11 14 char data[100] = "Hi!"; //data output
askksa12543 2:11f32d8cfa11 15 int i = 0, j = 128; //increment variables
askksa12543 0:7c7f4b30d64f 16
askksa12543 0:7c7f4b30d64f 17 int main() {
askksa12543 0:7c7f4b30d64f 18
askksa12543 0:7c7f4b30d64f 19 //turn on red led to show programming has worked
askksa12543 0:7c7f4b30d64f 20 myled = 0;
askksa12543 0:7c7f4b30d64f 21 //initialize output pins
askksa12543 0:7c7f4b30d64f 22 clock_pin = 0;
askksa12543 0:7c7f4b30d64f 23 serial_out = 0;
askksa12543 0:7c7f4b30d64f 24 //skew flag
askksa12543 0:7c7f4b30d64f 25 skew_flag = 1;
askksa12543 0:7c7f4b30d64f 26 //set timers
askksa12543 1:4c0c28cc2b2c 27 msecs = 2000;
askksa12543 1:4c0c28cc2b2c 28 sksecs = 1800;
askksa12543 0:7c7f4b30d64f 29
askksa12543 0:7c7f4b30d64f 30 //output a clock pulse and data.
askksa12543 2:11f32d8cfa11 31 while(i < 3)
askksa12543 0:7c7f4b30d64f 32 {
askksa12543 0:7c7f4b30d64f 33 //start timer for clock
askksa12543 0:7c7f4b30d64f 34 t.start();
askksa12543 0:7c7f4b30d64f 35 //wait until the timer has reached the set time.
askksa12543 0:7c7f4b30d64f 36 while(t.read_ms() < msecs)
askksa12543 0:7c7f4b30d64f 37 {
askksa12543 2:11f32d8cfa11 38 //extract data just before clock goes high
askksa12543 0:7c7f4b30d64f 39 if(!clock_pin && skew_flag && t.read_ms() > sksecs)
askksa12543 0:7c7f4b30d64f 40 {
askksa12543 2:11f32d8cfa11 41 //extract data bit
askksa12543 2:11f32d8cfa11 42 serial_out = (data[i] / j) % 2;
askksa12543 0:7c7f4b30d64f 43 skew_flag = 0;
askksa12543 2:11f32d8cfa11 44 j /= 2; //decrement j to get to next bit location
askksa12543 0:7c7f4b30d64f 45 }
askksa12543 0:7c7f4b30d64f 46 }
askksa12543 0:7c7f4b30d64f 47 //stop and reset the timer
askksa12543 0:7c7f4b30d64f 48 t.stop();
askksa12543 0:7c7f4b30d64f 49 t.reset();
askksa12543 0:7c7f4b30d64f 50 //switch clock signal
askksa12543 0:7c7f4b30d64f 51 clock_pin = !clock_pin;
askksa12543 0:7c7f4b30d64f 52 //reset skew flag
askksa12543 0:7c7f4b30d64f 53 skew_flag = 1;
askksa12543 2:11f32d8cfa11 54 //last bit sent - reset/increment variables
askksa12543 2:11f32d8cfa11 55 if(j==0)
askksa12543 2:11f32d8cfa11 56 {
askksa12543 2:11f32d8cfa11 57 j=128;
askksa12543 2:11f32d8cfa11 58 i++;
askksa12543 2:11f32d8cfa11 59 }
askksa12543 0:7c7f4b30d64f 60 }
askksa12543 1:4c0c28cc2b2c 61 }
askksa12543 1:4c0c28cc2b2c 62
askksa12543 2:11f32d8cfa11 63 //crc = x^4+x+1