Diff: buffer.cpp

Revision:

90:38dfa3f350aa

Child:

91:cd9fcd45ecf6

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/buffer.cpp	Thu Aug 17 02:42:30 2017 +0000
@@ -0,0 +1,79 @@
+/*buffer.cpp creates the circular buffer array and contains functions
+responsible for pushing new data on to the queue and also pulling data
+from it. It also contains the function to workout the moving average of
+the 10 values stored within the circular buffer*/
+
+#include "mbed.h"
+#include "rtos.h"
+#include "buffer.h"
+
+//Creates a struct array, using the custom struct that holds the acceleration measurements.
+AccelData circular_buffer_array[10];
+
+int rear = 0;
+int front = 0;
+int32_t sumX;
+int32_t sumY;
+int32_t sumZ;
+int32_t averageX;
+int32_t averageY;
+int32_t averageZ;
+
+//Pushes data on to buffer using modulo operation.
+void log_push(AccelData data) {
+
+  rear = (rear + 1) % 10;
+
+  if (rear == front) {
+    front = (front + 1) % 10;
+  }
+
+  circular_buffer_array[rear] = data;
+
+}
+
+//Retrieves a single data struct using the argument to specify which.
+AccelData log_get(int index)
+{
+
+  AccelData record;
+  record = circular_buffer_array[(front + index) % 10];
+
+  return record;
+
+}
+
+/*This function loops through the array and calculates the average.
+It clears the sum totals each time around so that the average is
+updated with the new value pushed on to the buffer, creating a 
+moving average*/
+void print_averages(){
+
+    while(1){
+
+    for (int i = 0; i < 10; i++) {
+
+      AccelData entry = log_get(i);
+      sumX += entry.x;
+      sumY += entry.y;
+      sumZ += entry.z;
+      
+      /*The two lines below can be uncomented to show the circular buffer working by
+      outputting the contents of the buffer every time a peice of data is pushed on to it.
+      This also makes it possible to verify the average is correct.*/
+      
+      //printf("LSM6DS0 [acc/mg]:      %6ld, %6ld, %6ld\r\n", entry.x, entry.y, entry.z);
+      //printf("\r\n");
+      
+    }
+
+    averageX = sumX / 10;
+    averageY = sumY / 10;
+    averageZ = sumZ / 10;
+    printf("average [acc/mg]:      %6ld, %6ld, %6ld\r\n", averageX, averageY, averageZ);
+    printf("\r\n");
+    sumX = 0;
+    sumY = 0;
+    sumZ = 0;
+}
+}