Diff: main.cpp

Revision:

0:da8a31f3e0f7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Sep 26 21:14:47 2016 +0000
@@ -0,0 +1,143 @@
+/**
+ * @brief Simple threading using the mbed os demo
+ */
+#include "mbed.h"
+#include "rtos.h"
+#include "ST7567.h"
+
+/* LCD and font parameters */
+#define LCD_HEIGHT          64
+#define LCD_WIDTH           128
+#define FONT_HEIGHT         10
+#define FONT_WIDTH          5
+
+
+/* allocate statically stacks for the three threads */
+unsigned char rt_stk[1024];
+unsigned char hp_stk[1024];
+unsigned char lp_stk[1024];
+
+/* creates three tread objects with different priorities */
+Thread real_time_thread(osPriorityRealtime, 1024, &rt_stk[0]);
+Thread high_prio_thread(osPriorityHigh, 1024, &hp_stk[0]);
+Thread low_prio_thread(osPriorityNormal, 1024, &lp_stk[0]);
+
+
+/* create a semaphore to synchronize the threads */
+Semaphore sync_sema;
+
+/* creates a instance of display */
+ST7567  disp(D11, D13, D12, D9, D10);
+
+
+
+
+/**
+ * @brief real time prio task function 
+ */
+static void rt_task(void) {
+    const char rt_message[] = {"Real time prio Task: \0"};
+    
+    disp.locate(0, FONT_HEIGHT * 2);        
+    
+    disp.printf(rt_message);
+    
+    for(;;) {
+        
+        /* take the semaphore allowing less priority
+         * tasks to run 
+         */
+         disp.locate(LCD_WIDTH - (sizeof(rt_message) * FONT_WIDTH), FONT_HEIGHT * 2);
+         disp.printf("WAIT!");
+         sync_sema.wait(0);
+        
+         /* show the message by 1 second */
+         disp.locate(LCD_WIDTH - (sizeof(rt_message) * FONT_WIDTH), FONT_HEIGHT * 2);
+         disp.printf("EXEC!");  
+
+         disp.locate(LCD_WIDTH - (sizeof(rt_message) * FONT_WIDTH), FONT_HEIGHT * 2);
+         disp.printf("DELAY");
+         Thread::wait(50);  
+                
+    }
+    
+}
+
+/**
+ * @brief high prio task function 
+ */
+static void hp_task(void){
+    const char hp_message[] = {"High priority Task: \0"};
+    
+    disp.locate(0, FONT_HEIGHT * 3);
+    disp.printf(hp_message);
+    
+    for(;;) {
+        /* take the semaphore allowing less priority
+         * tasks to run 
+         */
+         disp.locate(LCD_WIDTH - (sizeof(hp_message) * FONT_WIDTH), FONT_HEIGHT * 3);
+         disp.printf("WAIT!");
+         sync_sema.wait(0);
+        
+         /* show the message by 1 second */
+         disp.locate(LCD_WIDTH - (sizeof(hp_message) * FONT_WIDTH), FONT_HEIGHT * 3);
+         disp.printf("EXEC!");  
+
+         disp.locate(LCD_WIDTH - (sizeof(hp_message) * FONT_WIDTH), FONT_HEIGHT * 3);
+         disp.printf("DELAY");
+         Thread::wait(50);  
+
+    }
+}
+
+/**
+ * @brief normal prio task function 
+ */
+static void np_task(void) {
+    
+    const char lp_message[] = {"Low priority Task: \0"};
+    
+    disp.locate(0, FONT_HEIGHT * 4);
+    disp.printf(lp_message);
+
+    
+    for(;;) {
+         /* show the message by 1 second */
+         disp.locate(LCD_WIDTH - (sizeof(lp_message) * FONT_WIDTH), FONT_HEIGHT * 4);
+         disp.printf("EXEC!");  
+
+         disp.locate(LCD_WIDTH - (sizeof(lp_message) * FONT_WIDTH), FONT_HEIGHT * 4);
+         disp.printf("DELAY");
+         Thread::wait(50);  
+         
+         /* release the semaphore and syncrhonize the tasks */
+         disp.locate(LCD_WIDTH - (sizeof(lp_message) * FONT_WIDTH), FONT_HEIGHT * 4);
+         disp.printf("WAIT!");
+         sync_sema.release();
+
+    }
+}
+
+/**
+ * @brief main loop 
+ */
+int main(void) {
+    const char banner[] = {"Embarcados MBED-OS Thread demo\0"};
+
+    /* configures the display */
+    disp.cls();
+    disp.set_contrast(0x35);
+    disp.locate((LCD_WIDTH - (sizeof(banner) * FONT_WIDTH)) / 2, 0);
+    disp.printf(banner);
+
+
+    /* starts the three tasks */
+    real_time_thread.start(rt_task);   
+    high_prio_thread.start(hp_task);   
+    low_prio_thread.start(np_task);   
+
+
+    return 0;
+}
+