SerialInterrupt

Published 24 Jan 2010, by John Leimgruber

bug, interrupt, Serial

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main.cpp

00001 #include "mbed.h"
00002 
00003 // Test app to cause program to suddently terminate when using serial interrupt...
00004 // Line 24 seems to be the important bit, but I don't really understand why?
00005 // Is it perhaps the putc is peroperly clearing the interrupt flag instead of the getc?
00006 
00007 
00008 // usb serial device defaults to 9600 baud, 8N1 on /dev/ttyACM0 (in Linux!)
00009 Serial pc(USBTX, USBRX); // tx, rx
00010 
00011 // debugging LEDs
00012 DigitalOut interrupt(LED1);
00013 DigitalOut tx(LED4);
00014 
00015 // one byte receive buffer
00016 char rx_byte;
00017 
00018 void handle()
00019 {
00020   interrupt = 1;
00021   //if(pc.readable()) // <--- this line doesn't matter either way...
00022   {
00023     rx_byte = pc.getc();
00024     //pc.putc(rx_byte);  // <--- WITHOUT THIS LINE, THE APPLICATION WILL HANG IF IT RECEIVES WHILE SENDING!
00025   }
00026   interrupt = 0;
00027   return;
00028 }
00029 
00030 int main()
00031 {
00032   interrupt = 0;
00033   tx = 0;
00034   pc.attach(handle);
00035   
00036   while(1) 
00037   {
00038     // send a long string of bytes 
00039     tx = 1;
00040     for(int i=0;i<20;i++)
00041     {
00042       pc.printf("If I receive while transmitting this I will crash...\r\n");
00043     }
00044     tx = 0;
00045     
00046     wait(1.0);
00047   }
00048 }