Diff: main.cpp

Revision:

0:0ad38420d207

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Nov 22 08:40:56 2013 +0000
@@ -0,0 +1,157 @@
+#include "mbed.h"
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+DigitalIn button(D0);
+
+Timer timer;
+
+static void experiment1()
+{
+    unsigned int variableToHoldValue;     //declare a 32-bit variable
+    unsigned char *pBytePointer;          //declare a byte-pointer
+
+    pc.printf("\nThis is a first test...\n");
+    pc.printf("that printf() works - and it does!");
+
+    //store value in 32-bit variable
+    variableToHoldValue = 0x0AC0FFEE;
+
+    //set the byte-pointer to the beginning (first byte) of the 32-bit variable
+    pBytePointer = (unsigned char *)&variableToHoldValue;
+
+    //Test if big-endian
+    if ((*pBytePointer     == 0x0A) &&
+            (*(pBytePointer+1) == 0xC0) &&
+            (*(pBytePointer+2) == 0xFF) &&
+            (*(pBytePointer+3) == 0xEE)) {
+        pc.printf("\nThe CPU is a Big-endian system\n");
+    }
+
+    //Test if little-endian instead
+    else if ((*pBytePointer     == 0xEE) &&
+             (*(pBytePointer+1) == 0xFF) &&
+             (*(pBytePointer+2) == 0xC0) &&
+             (*(pBytePointer+3) == 0x0A)) {
+        pc.printf("\nThe CPU is a Little-endian system\n");
+    }
+    //Neither if the tests was correct – something is VERY wrong here!!!
+    else {
+        pc.printf("\nSomething is VERY wrong here!!!\n");
+    }
+
+    while(1)
+        ;
+}
+
+static void experiment2()
+{
+    // Enable button
+    button.mode(PullUp);
+
+    // Enter forever loop
+    while(1) {
+        // Wait for button to be pressed and then released
+        while(button) {
+        }
+        pc.printf("Button was pressed...\n");
+        while(!button) {
+        }
+        pc.printf("and released\n");
+    }
+}
+
+static void experiment3_alt1()
+{
+    pc.printf("This is a test of getc()...\n");
+    
+    // Enter forever loop
+    while(1) {
+        int rxChar = pc.getc();
+        pc.printf("Got %c\n", rxChar);
+    }
+}
+
+static void experiment3_alt2()
+{
+    int val = 0;
+    int numChars = 0;
+    pc.printf("This is a test of getc() and converts to a number...\n");
+    
+    // Enter forever loop
+    while(1) {
+        int rxChar = pc.getc();
+        numChars++;
+        if ((rxChar == '\r') || (rxChar == '\n') || (rxChar == ' ')) {
+            // Found a separator character, print number and start over
+            if (numChars > 1) {            
+                pc.printf("Found %d\n", val);
+            }
+            numChars = 0;
+            val = 0;
+        }
+        else if ((rxChar < '0') || (rxChar > '9')) {
+            // Not a number, reset and start looking again
+            pc.printf("Not a number: '%c'\n", rxChar);
+            numChars = 0;
+            val = 0;
+        }
+        else {
+            // A valid number was found
+            val = (val * 10) + (rxChar - '0');
+            if (numChars == 9) {
+                // Almost reached maximum size, print and continue
+                pc.printf("Found %d\n", val);
+                numChars = 0;
+                val = 0;
+            }
+        }
+    }
+}
+
+static void experiment4()
+{
+#define BYTES_IN_BUFF      512
+#define NUM_BUFFS_TO_SEND   10
+
+    // Change baudrate here to see what difference it makes. Don't forget
+    // to change to the same value on the Host PC
+    //pc.baud(115200);
+
+    pc.printf("This is a performance test...\n");
+    
+    char buff[BYTES_IN_BUFF + 1];
+ 
+    // initialize the buffer with some characters to print
+    for (int i = 0; i < BYTES_IN_BUFF; i+=10) {
+        for (int c = 0; c < 10; c++) {
+            buff[i+c] = '0' + c;
+        }
+    }
+ 
+    // puts expects the string to be null terminated
+    buff[BYTES_IN_BUFF] = '\0';
+    
+    timer.start();
+    int begin = timer.read_ms();
+    for (int num = 0; num < NUM_BUFFS_TO_SEND; num++) {        
+        pc.puts(buff);
+    }
+    int end = timer.read_ms();
+    timer.stop();
+ 
+    // print information about how much time passed and the bitrate
+    printf("\n--- Sent %d bytes in %dms\n", BYTES_IN_BUFF * NUM_BUFFS_TO_SEND, end-begin);
+    
+    while(1)
+        ;
+}
+
+int main()
+{
+    //experiment1();      // Detects endian
+    //experiment2();      // Button
+    //experiment3_alt1(); // getc
+    //experiment3_alt2(); // getc with digits
+    experiment4();        // performance
+}
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