Revision 14:655c1d3a5d59, committed 2016-02-16

Comitter:

apalmieri

Date:

Tue Feb 16 09:50:42 2016 +0000

Parent:

13:9ea386e57527

Child:

15:923ab55e8d5d

Commit message:

Add utilities to convert from uint8 to uint16 (and viceversa), and fix issue on casting to uint16*

Changed in this revision

--- a/DevSPI/DevSPI.h	Tue Feb 16 09:44:32 2016 +0000
+++ b/DevSPI/DevSPI.h	Tue Feb 16 09:50:42 2016 +0000
@@ -42,7 +42,7 @@
 
 /* Includes ------------------------------------------------------------------*/
 #include "mbed.h"
-
+extern DigitalOut led;
 /* Classes -------------------------------------------------------------------*/
 /** Helper class DevSPI providing functions for SPI communication common for a
  *  series of SPI devices.
@@ -105,12 +105,19 @@
         ssel = 0;
         
         /* Write data. */
-        if (_bits == 16)
-            for (int i = 0; i < NumBytesToWrite; i += 2)
-                write(((uint16_t *) pBuffer)[i]);
-        else if(_bits == 8)
-            for (int i = 0; i < NumBytesToWrite; i++)
+        if (_bits == 16) {
+            uint16_t dataToWrite;
+            for (int i = 0; i < NumBytesToWrite; i += 2) {
+                dataToWrite = convertFrom8To16(pBuffer);
+                write(dataToWrite);
+                pBuffer += sizeof(uint16_t);
+            }
+
+        } else if(_bits == 8) {
+            for (int i = 0; i < NumBytesToWrite; i++) {
                 write(pBuffer[i]);
+            }
+        }
 
         /* Unselect the chip. */
         ssel = 1;
@@ -133,12 +140,19 @@
         ssel = 0;
         
         /* Read data. */
-        if (_bits == 16)
-            for (int i = 0; i < NumBytesToRead; i += 2)
-                ((uint16_t *) pBuffer)[i] = write(0x00);
-        else if(_bits == 8)
-            for (int i = 0; i < NumBytesToRead; i++)
+        if (_bits == 16) {
+            uint16_t dataToRead;
+            for (int i = 0; i < NumBytesToRead; i += 2) {
+                dataToRead = write(0x00);
+                convertFrom16To8(dataToRead, pBuffer);
+                pBuffer += sizeof(uint16_t);
+            }
+
+        } else if(_bits == 8) {
+            for (int i = 0; i < NumBytesToRead; i++) {
                 pBuffer[i] = write(0x00);
+            }
+        }
 
         /* Unselect the chip. */
         ssel = 1;
@@ -162,18 +176,62 @@
         ssel = 0;
         
         /* Read and write data at the same time. */
-        if (_bits == 16)
-            for (int i = 0; i < NumBytes; i += 2)
-                ((uint16_t *) pBufferToRead)[i] = write(((uint16_t *) pBufferToWrite)[i]);
-        else if(_bits == 8)
-            for (int i = 0; i < NumBytes; i++)
+        if (_bits == 16) {
+            uint16_t dataToRead;
+            uint16_t dataToWrite;
+
+            for (int i = 0; i < NumBytes; i += 2) {
+                dataToWrite = convertFrom8To16(pBufferToWrite);
+                
+                dataToRead = write(dataToWrite);
+                
+                convertFrom16To8(dataToRead, pBufferToRead);
+                
+                pBufferToWrite += sizeof(uint16_t);
+                pBufferToRead += sizeof(uint16_t);
+            }
+
+        } else if(_bits == 8) {
+            for (int i = 0; i < NumBytes; i++) {
                 pBufferToRead[i] = write(pBufferToWrite[i]);
+            }
+        }
 
         /* Unselect the chip. */
         ssel = 1;
 
         return 0;
     }
+
+private:
+
+    /**
+     * @brief      Converts two uint8_t words into one of uint16_t
+     * @param[in]  ptr pointer to the buffer of data to be converted.
+     * @retval     16-bit data.
+     */
+    uint16_t convertFrom8To16(uint8_t *ptr)
+    {
+        uint16_t data16 = 0x0000;
+        
+        data16 = *ptr;
+        data16 |= *(++ptr) << 8;
+        
+        return data16;
+    }
+
+    /**
+     * @brief      Converts one uint16_t word into two uint8_t
+     * @param[in]  ptr pointer to the buffer of uint8_t words.
+     * @param[in]  16-bit data.
+     * @retval     none.
+     */
+    void convertFrom16To8(uint16_t data16, uint8_t *ptr)
+    {
+        *(ptr) = data16 & 0x00FF;
+        *(++ptr) = (data16 >> 8) & 0x00FF;
+    }
+
 };
 
 #endif /* __DEV_SPI_H */