main.cpp

00001 /*Program Example 7.6: I2C Slave, when called transfers switch state to mbed acting as Master, and displays state of Master's switches on its leds.
00002                                                                               */
00003 
00004 #include <mbed.h>
00005 I2CSlave slave(p9, p10);          //Configure I2C slave
00006 DigitalOut red_led(p25);          //red led
00007 DigitalOut green_led(p26);        //green led
00008 DigitalIn  switch_ip1(p5);
00009 DigitalIn  switch_ip2(p6);
00010 char switch_word ;                //word we will send
00011 char recd_val;                    //value received from master
00012 
00013 int main()
00014 {
00015     slave.address(0x52);
00016     while (1) {
00017         //set up switch_word from switches that are pressed
00018         switch_word=0xa0; //set up a recognisable output pattern
00019         if (switch_ip1==1)
00020             switch_word=switch_word|0x01;
00021         if (switch_ip2==1)
00022             switch_word=switch_word|0x02;
00023         slave.write(switch_word); //load up word to send
00024         //test for I2C, and act accordingly
00025         int i = slave.receive();
00026         if (i == 3) {           //slave is addressed, Master will write
00027             recd_val= slave.read();
00028         }
00029         //set leds according to incoming word from slave
00030         red_led=0;              //preset both to 0
00031         green_led=0;
00032         recd_val=recd_val&0x03; //AND out unwanted bits
00033         if (recd_val==1)
00034             red_led=1;
00035         if (recd_val==2)
00036             green_led=1;
00037         if (recd_val==3) {
00038             red_led=1;
00039             green_led=1;
00040         }
00041     }
00042 }
00043