Revision 26:71c54c8ae536, committed 2016-05-08

Comitter:

stwykd

Date:

Sun May 08 08:37:33 2016 +0000

Parent:

25:55c0dc5b32b3

Child:

27:0bbc1d575986

Commit message:

Created a buffer and finished implementing expansion board.; There's missing to send the data to the buffer just after reading on readData. You can copy and paste buffer.cpp to mailbox.cpp, or continue buffer.cpp as a mailbox

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/buffer.cpp	Sun May 08 08:37:33 2016 +0000
@@ -0,0 +1,77 @@
+#include "mbed.h"
+#include "rtos.h"
+#include "string.h"
+#include <stdio.h>
+#include <ctype.h>
+
+// A First-In-First-Out buffer is used with streams of data.
+// It is thread-safe and often used to buffer data across threads
+
+#define BUFFERSIZE 100
+
+typedef struct {
+        uint8_t   id;
+        float    tempCelcius;
+        float    tempFarenheit;
+        float    humidity;
+        float    pressure;
+        int      accelerometer;
+        int      gyroscope;
+        int      magnetometer;
+        char*    date;
+    } log_data;
+
+Semaphore *spaceAvailable;
+Semaphore *samplesInBuffer;
+Mutex *bufferLock;
+
+log_data buffer[BUFFERSIZE];
+unsigned int newestIndex = BUFFERSIZE-1;
+unsigned int oldestIndex = BUFFERSIZE-1;
+
+class Buffer {
+public:
+    void addDataToQueue(log_data d) {
+    // Check whether there's space
+    int32_t Nspaces = spaceAvailable->wait();
+    
+    // If there's space, use the mutex
+    bufferLock->lock();
+    
+    // Update buffer
+    newestIndex = (newestIndex+1) % BUFFERSIZE;
+    buffer[newestIndex] = d;
+    printf("\tAdded log_data id %d to buffer, %d space available\n",
+        unsigned(d.id), Nspaces-1);
+    
+    bufferLock->unlock();
+    
+    // Signal that a sample has been added
+    samplesInBuffer->release();
+    }
+    
+    log_data takeCharacterFromQueue(){
+    // Check whether there are samples
+    int32_t Nsamples = samplesInBuffer->wait();
+    
+    bufferLock->lock();
+    
+    oldestIndex = (oldestIndex+1) % BUFFERSIZE;
+    log_data d = buffer[oldestIndex];
+    printf("\tRemoved log_data id %d from buffer, %d bytes remaining\n",
+        unsigned(d.id), Nsamples-1);
+    
+    bufferLock->unlock();
+    
+    //Signal there's space in the buffer
+    spaceAvailable->release();
+    
+    return d;
+    }
+    
+    Buffer() {
+        bufferLock = new Mutex();
+        spaceAvailable = new Semaphore(BUFFERSIZE);
+        samplesInBuffer = new Semaphore(0);
+    }
+};
\ No newline at end of file

--- a/expansionBoard.cpp	Sun May 08 07:00:11 2016 +0000
+++ b/expansionBoard.cpp	Sun May 08 08:37:33 2016 +0000
@@ -1,5 +1,6 @@
 #include "mbed.h"
 #include "x_nucleo_iks01a1.h"
+#include "buffer.cpp"
 
 /* Instantiate the expansion board */
 static X_NUCLEO_IKS01A1 *mems_expansion_board = X_NUCLEO_IKS01A1::Instance(D14, D15);