main.cpp

00001 #include "mbed.h"
00002 
00003 /* to test if code loaded properly
00004  */
00005 DigitalOut myled(LED2);
00006 
00007 // to power the rf module 
00008 DigitalOut power(p30);
00009 DigitalOut powerStatus(LED1);
00010 
00011 /* for time division multiplexing.
00012  * when an rf tx requires to send signals,
00013  * it request the other own operating at the same
00014  * freqeuncy to shut itself down. The other module also
00015  * follows the same behavioural code!
00016  */
00017 InterruptIn inRequest(p5);
00018 DigitalOut outRequest(p6);
00019 
00020 
00021 Serial tx(p9, p10); 
00022 Serial pc(USBTX, USBRX);
00023 
00024 // turn RF tx off
00025 void turnOffRF() { 
00026     power = 0;
00027     powerStatus = 0;
00028 }
00029 
00030 // turn RF tx on
00031 void turnOnRF() {
00032     power = 1;
00033     powerStatus = 1;
00034 }
00035 
00036 // send a request to the other RF tx to kindly shut down
00037 void sendRequest() {
00038     outRequest = 0;
00039     wait(0.1);
00040     outRequest = 1;
00041 }
00042 
00043 int main() 
00044 {
00045     power = 0; // power to the RF tx
00046     powerStatus = 0; // power status of the RF tx
00047     myled = 1;
00048     char msg[10];
00049 
00050     tx.baud(2400);
00051     
00052     /* turn RF tx off when requested by the other tx
00053      */
00054     inRequest.rise(turnOffRF);
00055     
00056     turnOffRF();
00057     
00058     /* read messages from the serial port of the computer
00059      * and broadcast them
00060      */
00061     while (1) { 
00062         while (pc.readable()) {
00063             if (power == 0) {
00064                 sendRequest(); // send request to the other RF tx to shut itself down.
00065                 turnOnRF();
00066             }
00067             msg[0] = pc.getc();
00068             tx.putc(msg[0]);
00069             pc.putc(msg[0]);
00070         }
00071        
00072     }
00073 }