Diploma Thesis in Aerospace Engineering, January 2014

Diff: MODSERIAL/example2.cpp

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+/*
+    Copyright (c) 2011 Andy Kirkham
+ 
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+ 
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+ 
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+    
+    @file          example2.cpp 
+    @purpose       Demos a simple messaging system.
+    @version       see ChangeLog.c
+    @date          Jan 2011
+    @author        Andy Kirkham
+*/
+
+/*
+    This example demostrates a simple "messaging" system. You can use it with
+    a terminal program to test it out or write a cusom C#/C++/VB/etc program
+    to read and write messages to or from the Mbed. The default baud rate in
+    this example is 115200.
+    
+    In this example, the LEDs are controlled and pins p21 to p24 are set as
+    InterruptIn and send messages out when their value changes.
+    
+    To use, hook up the MBed USB and open your fav terminal. All messages
+    end with the \n character, don't forget to hit carriage return!. 
+    As an example:-
+        
+        to switch on LED1 send LED1:1\n, off is LED1:0\n and toggle is LED1:2\n
+        to switch on LED2 send LED2:1\n, off is LED2:0\n and toggle is LED2:2\n
+        to switch on LED3 send LED3:1\n, off is LED3:0\n and toggle is LED3:2\n
+        to switch on LED4 send LED4:1\n, off is LED4:0\n and toggle is LED4:2\n
+        
+    When a pin change on p21 to p24 happens, a message is sent. As an example
+    when p21 goes low PIN21:0\n is sent, when goes high PIN21:1\n is sent.
+    
+    Note, the InterruptIn pins p21 to p24 are setup to have pullups. This means
+    they are high. To activate them use a wire to short the pin to 0volts.
+    
+    If you find that p21 to p24 sent a lot of on/off/on/off then it's probably
+    due to "bounce". If you are connecting a mechanical switch to a pin you
+    may prefer to use the PinDetect library rather than using InterruptIn.
+    @see http://mbed.org/users/AjK/libraries/PinDetect/latest
+    
+    One point you may notice. Incoming messages are processed via main()'s
+    while(1) loop whereas pin changes have their messages directly sent.
+    The reason for this is when MODSERIAL makes callbacks to your application
+    it is in "interrupt context". And one thing you want to avoid is spending
+    lots of CPU time in that context. So, the callback moves the message from
+    the input buffer to a local holding buffer and it then sets a bool flag
+    which tells main()'s while(1) loop to process that buffer. This means the 
+    time spent doing the real incoming message handing is within your program
+    and not within MODSERIAL's interrupt context. So you may ask, why not do
+    the same for out going messages? Well, because MODSERIAL output buffers
+    all your sent content then sending chars is very fast. MODSERIAL handles
+    all the nitty gritty bits for you. You can just send. This example uses
+    puts() to send the message. If you can, always try and use sprintf()+puts()
+    rathe than printf(), printf() is known to often screw things up when used
+    within an interrupt context. Better still, just use puts() and do away
+    with any of the crappy ?printf() calls if possible. But I found the code
+    below to work fine even at 115200baud.
+    
+*/
+
+
+#ifdef COMPILE_EXAMPLE1_CODE_MODSERIAL
+
+#include "mbed.h"
+#include "MODSERIAL.h"
+
+#define MESSAGE_BUFFER_SIZE 32
+
+DigitalOut led1(LED1);
+DigitalOut led2(LED2);
+DigitalOut led3(LED3);
+DigitalOut led4(LED4);
+
+InterruptIn P21(p21);
+InterruptIn P22(p22);
+InterruptIn P23(p23);
+InterruptIn P24(p24);
+
+MODSERIAL messageSystem(USBTX, USBRX);
+
+char messageBufferIncoming[MESSAGE_BUFFER_SIZE];
+char messageBufferOutgoing[MESSAGE_BUFFER_SIZE];
+bool messageReceived;
+
+void messageReceive(MODSERIAL_IRQ_INFO *q) {
+    MODSERIAL *sys = q->serial;
+    sys->move(messageBufferIncoming, MESSAGE_BUFFER_SIZE);
+    messageReceived = true;
+    return 0;
+}
+
+void messageProcess(void) {
+         if (!strncmp(messageBufferIncoming, "LED1:1", sizeof("LED1:1")-1)) led1 = 1;
+    else if (!strncmp(messageBufferIncoming, "LED1:0", sizeof("LED1:0")-1)) led1 = 0;
+    else if (!strncmp(messageBufferIncoming, "LED1:2", sizeof("LED1:2")-1)) led1 = !led1;
+    
+    else if (!strncmp(messageBufferIncoming, "LED2:1", sizeof("LED2:1")-1)) led2 = 1;
+    else if (!strncmp(messageBufferIncoming, "LED2:0", sizeof("LED2:0")-1)) led2 = 0;
+    else if (!strncmp(messageBufferIncoming, "LED2:2", sizeof("LED2:2")-1)) led2 = !led2;
+    
+    else if (!strncmp(messageBufferIncoming, "LED3:1", sizeof("LED3:1")-1)) led3 = 1;
+    else if (!strncmp(messageBufferIncoming, "LED3:0", sizeof("LED3:0")-1)) led3 = 0;
+    else if (!strncmp(messageBufferIncoming, "LED3:2", sizeof("LED3:2")-1)) led3 = !led3;
+    
+    else if (!strncmp(messageBufferIncoming, "LED4:1", sizeof("LED4:1")-1)) led4 = 1;
+    else if (!strncmp(messageBufferIncoming, "LED4:0", sizeof("LED4:0")-1)) led4 = 0;
+    else if (!strncmp(messageBufferIncoming, "LED4:2", sizeof("LED4:2")-1)) led4 = !led4;
+    
+    messageReceived = false;
+}
+
+#define PIN_MESSAGE_SEND(x,y) \
+    sprintf(messageBufferOutgoing,"PIN%02d:%d\n",x,y);\
+    messageSystem.puts(messageBufferOutgoing);
+
+void pin21Rise(void) { PIN_MESSAGE_SEND(21, 1); }
+void pin21Fall(void) { PIN_MESSAGE_SEND(21, 0); }
+void pin22Rise(void) { PIN_MESSAGE_SEND(22, 1); }
+void pin22Fall(void) { PIN_MESSAGE_SEND(22, 0); }
+void pin23Rise(void) { PIN_MESSAGE_SEND(23, 1); }
+void pin23Fall(void) { PIN_MESSAGE_SEND(23, 0); }
+void pin24Rise(void) { PIN_MESSAGE_SEND(24, 1); }
+void pin24Fall(void) { PIN_MESSAGE_SEND(24, 0); }
+
+int main() {
+
+    messageReceived = false;
+    messageSystem.baud(115200);
+    messageSystem.attach(&messageReceive, MODSERIAL::RxAutoDetect);
+    messageSystem.autoDetectChar('\n'); 
+
+    // Enable pullup resistors on pins.
+    P21.mode(PullUp); P22.mode(PullUp); P23.mode(PullUp); P24.mode(PullUp);
+    
+    // Fix Mbed library bug, see http://mbed.org/forum/bugs-suggestions/topic/1498
+    LPC_GPIOINT->IO2IntClr = (1UL << 5) | (1UL << 4) | (1UL << 3) | (1UL << 2); 
+    
+    // Attach InterruptIn pin callbacks.
+    P21.rise(&pin21Rise); P21.fall(&pin21Fall);
+    P22.rise(&pin22Rise); P22.fall(&pin22Fall);
+    P23.rise(&pin23Rise); P23.fall(&pin23Fall);
+    P24.rise(&pin24Rise); P24.fall(&pin24Fall);
+    
+    while(1) {
+        // Process incoming messages.
+        if (messageReceived) messageProcess();
+    }
+}
+
+#endif