Revision 14:5ee75b072c69, committed 2013-05-27

Comitter:

paulg

Date:

Mon May 27 09:58:51 2013 +0000

Parent:

13:52706c2a28f4

Commit message:

Enhanced test program using watchdog timer to recover from lock-up

Changed in this revision

diff -r 52706c2a28f4 -r 5ee75b072c69 main.cpp
--- a/main.cpp	Thu Mar 28 22:15:12 2013 +0000
+++ b/main.cpp	Mon May 27 09:58:51 2013 +0000
@@ -1,4 +1,9 @@
+// TCP Socket Test Program
+// Based on work by Daniel Peter: https://mbed.org/forum/mbed/topic/4354/
+// Modified to add LED tracing, a second task and watchdog timer recovery from lock-up
+
 #include "mbed.h"
+#include "rtos.h"
 #include "EthernetInterface.h"
 
 #define RETRIES_ALLOWED 5
@@ -6,11 +11,43 @@
 Serial pc(USBTX, USBRX);
 EthernetInterface eth;
 DigitalOut led1(LED1);
+DigitalOut led2(LED2), led3(LED3), led4(LED4);
+
+// Simon's Watchdog code from http://mbed.org/forum/mbed/topic/508/
+class Watchdog {
+public:
+// Load timeout value in watchdog timer and enable
+    void kick(float s) {
+        LPC_WDT->WDCLKSEL = 0x1;                // Set CLK src to PCLK
+        uint32_t clk = SystemCoreClock / 16;    // WD has a fixed /4 prescaler, PCLK default is /4
+        LPC_WDT->WDTC = s * (float)clk;
+        LPC_WDT->WDMOD = 0x3;                   // Enabled and Reset
+        kick();
+    }
+// "kick" or "feed" the dog - reset the watchdog timer
+// by writing this required bit pattern
+    void kick() {
+        LPC_WDT->WDFEED = 0xAA;
+        LPC_WDT->WDFEED = 0x55;
+    }
+};
+ 
+Watchdog wdt;   // Set up the watchdog timer
+
+void led2_thread(void const *args) {
+    while (true) {
+        led2 = !led2;
+        Thread::wait(250);
+    }
+}
 
 int main()
 {
+    int i = 0;
+    Thread thread(led2_thread);
 
     pc.baud(115200);
+    printf("TCP Socket Hello World Test\n");
     printf("Initialising...\n");
     set_time(0);
 
@@ -25,6 +62,10 @@
     // successful DHCP
     printf("IP Address is %s\n", eth.getIPAddress());
 
+    // set up a 10 second timeout on watchdog timer hardware
+    // needs to be longer than worst case main loop exection time
+    wdt.kick(10.0);  
+
     // loop forever
     while (true) {
 
@@ -42,7 +83,7 @@
         }
 
         // send command
-        printf("Sending at %d seconds\n", time(NULL));
+        printf("Sending (%d) at %d seconds\n", i++, time(NULL));
         char http_cmd[] = "GET /media/uploads/mbed_official/hello.txt HTTP/1.0\n\n";
         sock.send_all(http_cmd, sizeof(http_cmd) - 1);
 
@@ -54,18 +95,23 @@
             int result;
             char buffer[256];
 
+            led4 = 1;
             result = sock.receive(buffer, sizeof(buffer) - 1);
+            led4 = 0;
             printf("Received: %d %d %d\n", result, received, retries);
 
             // if timeout or no data
             if (result <= 0) {
 
                 // if data previously received then stop receiving
-                if (received > 0)
+                if (received > 0) {
+//                    printf("Data previously received\n");
                     break;
+                }
 
                 // if incremented retries exceeded then no response and stop receiving
                 if (++retries > RETRIES_ALLOWED) {
+                    printf("Retry limit exceeded\n");
                     break;
                 }
 
@@ -86,5 +132,7 @@
         // wait before repeating
         Thread::wait(1000);
 
+        // End of main loop so "kick" to reset watchdog timer and avoid a reset
+        wdt.kick();
     }
 }
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