AS5045.cpp

00001 #include "AS5045.h"
00002 //we have 5040
00003 /** Constructor
00004  *
00005  *  @param CS Pin number for the digital output
00006  *
00007  *  @note
00008  *      PinName CS is the digital output pin number
00009  */
00010 
00011 
00012 Timer timer_enc;
00013 AS5045::AS5045(PinName CS) :
00014     _spi(NC,D12, D13),  // MBED SPI init
00015     _cs(CS)             // Digital output pin init
00016 {
00017     // Set SPI bitwidth9
00018     _spi.format(8, 1);
00019 
00020     // Set SPI frequency
00021     _spi.frequency(SPI_FREQ);//SPI_FREQ);
00022     // Set the digital output high
00023     _cs = 1;
00024 }
00025 
00026 /** Read tick amount from encoder (position)
00027  *
00028  *  @note
00029  *      Tick amount is recieved through SPI
00030  */
00031 int AS5045::getPosition()
00032 {
00033     unsigned int upper,     // Upper part of the tick amount integer
00034              lower;     // Lower part of the tick amount integer
00035 //
00036 //    // Set the chip select pin low
00037 //    //timer_enc.reset();
00038 //    timer_enc.start();
00039 //    _cs = 0;
00040 //    
00041 //    wait_ms(1);
00042 //    // Read data from the encoder
00043 //    upper = (_spi.write(0x00)) ;
00044 ////    lower = (_spi.write(0x00));
00045 //
00046 ////    lower = lower >> 6;
00047 ////    upper = (upper >> 6)+lower;
00048 ////   upper = upper & 0xffc0;
00049 ////    upper = upper >> 6;
00050 //
00051 //    // Set the chip select pin high
00052 //    _cs = 1;
00053 //    //wait_ms(5);
00054     // Return full 9-bits tick amount
00055    // return (upper>>5);
00056     //return upper ;
00057     
00058     _cs = 0;
00059    upper = _spi.write(0x00);
00060    lower = _spi.write(0x00);
00061   _cs = 1;
00062  
00063  
00064     //upper &=~ 0xF0;//mask out the first 4 bits
00065 //     EncoderByteData  = upper << 8; //shift MSB to correct EncoderByteData in EncoderByteData message
00066 //     EncoderByteData  += lower; // add LSB to EncoderByteData message to complete message
00067   return ((upper << 2)|(lower >> 6));
00068   //return EncoderByteData; 
00069 }
00070 
00071 /** Convert position of the encoder to degrees
00072  *
00073  *  @note
00074  *      Tick amount is recieved internally
00075  */
00076 float AS5045::getAngle()
00077 {
00078     // Get data from the encoder
00079     float value = (float)getPosition();
00080 
00081     // Return degrees of rotation of the encoder
00082     return value * RESOLUTION;
00083 }