Diff: commHeaders/SPIcommFunctions.h

Revision:

0:e9cce1154246

Child:

1:4ea157704c58

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/commHeaders/SPIcommFunctions.h	Fri Feb 23 23:32:40 2018 +0000
@@ -0,0 +1,114 @@
+#define SPImode
+
+//=========================================================================
+//Communication pinouts for serial COM port, SPI, and interrupts
+//=========================================================================
+static Serial pc(USBTX, USBRX);                     //PC comm
+static SPI spi(p23, p24, p25);                      //mosi, miso, sclk
+static DigitalOut cs(p22);                          //chip select
+
+
+//=========================================================================
+//Variables and arrays used for communications and data storage
+//=========================================================================
+int8_t deltaX_low, deltaY_low;                      //Stores the low-bits of movement data.
+int16_t deltaX_high, deltaY_high;                   //Stores the high-bits of movement data.
+int16_t deltaX, deltaY;                             //Stores the combined value of low and high bits.
+int16_t totalX, totalY = 0;                         //Stores the total deltaX and deltaY moved during runtime.
+
+
+//=========================================================================
+//Functions used to communicate with the sensor and grab/print data
+//=========================================================================
+uint8_t readRegister(uint8_t addr);
+//This function takes an 8-bit address in the form 0x00 and returns an 8-bit value in the form 0x00.
+
+void writeRegister(uint8_t addr, uint8_t data);
+//This function takes an 8-bit address and 8-bit data. Writes the given data to the given address.
+
+void load(const uint8_t array[][2], uint8_t arraySize);
+//Takes an array of registers/data (found in registerArrays.h) and their size and writes in all the values.
+
+void grabData(void);
+//Grabs the deltaX and deltaY information from the proper registers and formats it into the proper format.
+
+void printData(void);
+//Prints the data out to a serial terminal.
+
+
+
+
+
+//=========================================================================
+//Functions definitions
+//=========================================================================
+uint8_t readRegister(uint8_t addr)
+{
+    cs = 0;                                 //Set chip select low/active
+    addr = addr & 0x7F;                     //Set MSB to 0 to indicate read operation
+    spi.write(addr);                        //Write the given address
+    wait_us(1);                             //Add a tiny delay after sending address for some internal cycle timing.
+    uint8_t data_read = spi.write(0x00);    //Throw dummy byte after sending address to receieve data
+    cs = 1;                                 //Set chip select back to high/inactive
+    return data_read;                       //Returns 8-bit data from register
+}
+
+
+//=========================================================================
+void writeRegister(uint8_t addr, uint8_t data)
+{
+    cs = 0;                         //Set chip select low/active
+    addr = addr | 0x80;             //Set MSB to 1 to indicate write operation
+    spi.write(addr);                //Write the given address
+    spi.write(data);                //Write the given data
+    cs = 1;                         //Set chip select back to high/inactive
+    
+    //pc.printf("R:%2X, D:%2X\n\r", addr, readRegister(addr));
+            //Uncomment this line for debugging. Prints every register write operation.
+}
+
+
+//=========================================================================
+void load(const uint8_t array[][2], uint8_t arraySize)
+{
+    for(uint8_t q = 0; q < arraySize; q++)
+    {
+        writeRegister(array[q][0], array[q][1]);    //Writes the given array of registers/data.
+    }
+}
+
+
+//=========================================================================
+void grabData(void)
+{
+    deltaX_low = readRegister(0x03);        //Grabs data from the proper registers.
+    deltaY_low = readRegister(0x04);
+    deltaX_high = (readRegister(0x12)<<4) & 0xF00;      //Grabs data and shifts it to make space to be combined with lower bits.
+    deltaY_high = (readRegister(0x12)<<8) & 0xF00;
+    
+    if(deltaX_high & 0x800)
+        deltaX_high |= 0xf000; // 12-bit data convert to 16-bit (two's comp)
+        
+    if(deltaY_high & 0x800)
+        deltaY_high |= 0xf000; // 12-bit data convert to 16-bit (2's comp)
+        
+    deltaX = deltaX_high | deltaX_low;      //Combined the low and high bits.
+    deltaY = deltaY_high | deltaY_low;
+}
+
+
+//=========================================================================
+void printData(void)
+{
+    if((deltaX != 0) || (deltaY != 0))      //If there is deltaX or deltaY movement, print the data.
+    {
+        totalX += deltaX;
+        totalY += deltaY;
+        
+        pc.printf("deltaX: %d\t\t\tdeltaY: %d\n\r", deltaX, deltaY);    //Prints each individual count of deltaX and deltaY.
+        pc.printf("X-axis Counts: %d\t\t\tY-axis Counts: %d\n\r", totalX, totalY);  //Prints the total movement made during runtime.
+    }
+    
+    deltaX = 0;                             //Resets deltaX and Y values to zero, otherwise previous data is stored until overwritten.
+    deltaY = 0;
+}