Rob Toulson / Mbed 2 deprecated PE_07-09_AsyncComms

by Rob Toulson and Tim Wilmshurst from textbook "Fast and Effective Embedded Systems Design: Applying the ARM mbed"

Dependencies:   mbed

main.cpp@0:75151492e147, 2012-10-15 (annotated)

Committer:
robt
Date:
Mon Oct 15 21:27:29 2012 +0000
Revision:
0:75151492e147
by Rob Toulson and Tim Wilmshurst from textbook "Fast and Effective Embedded Systems Design: Applying the ARM mbed"

Who changed what in which revision?

UserRevisionLine numberNew contents of line
robt 0:75151492e147 1 /*Program Example 7.9: Sets the mbed up for async communication, and exchanges data with a similar node, sending its own switch positions, and displaying those of the other.
robt 0:75151492e147 2 */
robt 0:75151492e147 3 #include "mbed.h"
robt 0:75151492e147 4 Serial async_port(p9, p10); //set up TX and RX on pins 9 and 10
robt 0:75151492e147 5 DigitalOut red_led(p25); //red led
robt 0:75151492e147 6 DigitalOut green_led(p26); //green led
robt 0:75151492e147 7 DigitalOut strobe(p7); //a strobe to trigger the scope
robt 0:75151492e147 8 DigitalIn switch_ip1(p5);
robt 0:75151492e147 9 DigitalIn switch_ip2(p6);
robt 0:75151492e147 10 char switch_word ; //the word we will send
robt 0:75151492e147 11 char recd_val; //the received value
robt 0:75151492e147 12
robt 0:75151492e147 13 int main() {
robt 0:75151492e147 14 async_port.baud(9600); //set baud rate to 9600 (ie default)
robt 0:75151492e147 15 //accept default format, of 8 bits, no parity
robt 0:75151492e147 16 while (1){
robt 0:75151492e147 17 //Set up the word to be sent, by testing switch inputs
robt 0:75151492e147 18 switch_word=0xa0; //set up a recognisable output pattern
robt 0:75151492e147 19 if (switch_ip1==1)
robt 0:75151492e147 20 switch_word=switch_word|0x01; //OR in lsb
robt 0:75151492e147 21 if (switch_ip2==1)
robt 0:75151492e147 22 switch_word=switch_word|0x02; //OR in next lsb
robt 0:75151492e147 23 strobe =1; //short strobe pulse
robt 0:75151492e147 24 wait_us(10);
robt 0:75151492e147 25 strobe=0;
robt 0:75151492e147 26 async_port.putc(switch_word); //transmit switch_word
robt 0:75151492e147 27 if (async_port.readable()==1) //is there a character to be read?
robt 0:75151492e147 28 recd_val=async_port.getc(); //if yes, then read it
robt 0:75151492e147 29
robt 0:75151492e147 30 //set leds according to incoming word from slave
robt 0:75151492e147 31 red_led=0; //preset both to 0
robt 0:75151492e147 32 green_led=0;
robt 0:75151492e147 33 recd_val=recd_val&0x03; //AND out unwanted bits
robt 0:75151492e147 34 if (recd_val==1)
robt 0:75151492e147 35 red_led=1;
robt 0:75151492e147 36 if (recd_val==2)
robt 0:75151492e147 37 green_led=1;
robt 0:75151492e147 38 if (recd_val==3){
robt 0:75151492e147 39 red_led=1;
robt 0:75151492e147 40 green_led=1;
robt 0:75151492e147 41 }
robt 0:75151492e147 42
robt 0:75151492e147 43 }
robt 0:75151492e147 44 }
robt 0:75151492e147 45