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Using FRDM Board to output data and a clock for communications example.
main.cpp
- Committer:
- askksa12543
- Date:
- 2015-03-15
- Revision:
- 2:11f32d8cfa11
- Parent:
- 1:4c0c28cc2b2c
- Child:
- 3:027d30718bbc
File content as of revision 2:11f32d8cfa11:
//project to include preamble, addressing, control, error control. //currently fixed size data field but doesn't have to be. (post amble if not fixed size) #include "mbed.h" #include "stdio.h" #define MAX 100 //set the size of the character data storage array DigitalOut myled(LED1); // red led on board DigitalOut clock_pin(D8), serial_out(D7); //send clock pulse and tx Timer t; //timer for controlling the clock and data skew int msecs, sksecs; //clock time needed for data transfer and skew time int skew_flag; //skew flag for while loop char data[100] = "Hi!"; //data output int i = 0, j = 128; //increment variables int main() { //turn on red led to show programming has worked myled = 0; //initialize output pins clock_pin = 0; serial_out = 0; //skew flag skew_flag = 1; //set timers msecs = 2000; sksecs = 1800; //output a clock pulse and data. while(i < 3) { //start timer for clock t.start(); //wait until the timer has reached the set time. while(t.read_ms() < msecs) { //extract data just before clock goes high if(!clock_pin && skew_flag && t.read_ms() > sksecs) { //extract data bit serial_out = (data[i] / j) % 2; skew_flag = 0; j /= 2; //decrement j to get to next bit location } } //stop and reset the timer t.stop(); t.reset(); //switch clock signal clock_pin = !clock_pin; //reset skew flag skew_flag = 1; //last bit sent - reset/increment variables if(j==0) { j=128; i++; } } } //crc = x^4+x+1