RHHardwareSPI.cpp

00001 // RHHardwareSPI.h
00002 // Author: Mike McCauley (mikem@airspayce.com)
00003 // Copyright (C) 2011 Mike McCauley
00004 // Contributed by Joanna Rutkowska
00005 // $Id: RHHardwareSPI.cpp,v 1.12 2015/07/01 00:46:05 mikem Exp $
00006 
00007 #include <RHHardwareSPI.h>
00008 
00009 // Declare a single default instance of the hardware SPI interface class
00010 RHHardwareSPI hardware_spi;
00011 
00012 
00013 // grab config from mbed_app.json
00014 SPI _SPI(RADIO_MOSI, RADIO_MISO, RADIO_SCLK);
00015 
00016 #define REVERSE_BITS(byte) (((reverse_lookup[(byte & 0x0F)]) << 4) + reverse_lookup[((byte & 0xF0) >> 4)])
00017     
00018 static const uint8_t reverse_lookup[] = { 0, 8,  4, 12, 2, 10, 6, 14,1, 9, 5, 13,3, 11, 7, 15 };
00019 
00020 
00021 // Arduino Due has default SPI pins on central SPI headers, and not on 10, 11, 12, 13
00022 // as per otherArduinos
00023 // http://21stdigitalhome.blogspot.com.au/2013/02/arduino-due-hardware-SPI.html
00024 #if defined (__arm__) && !defined(CORE_TEENSY)
00025  // Arduino Due in 1.5.5 has no definitions for SPI dividers
00026  // SPI clock divider is based on MCK of 84MHz  
00027  #define SPI_CLOCK_DIV16 (VARIANT_MCK/84000000) // 1MHz
00028  #define SPI_CLOCK_DIV8  (VARIANT_MCK/42000000) // 2MHz
00029  #define SPI_CLOCK_DIV4  (VARIANT_MCK/21000000) // 4MHz
00030  #define SPI_CLOCK_DIV2  (VARIANT_MCK/10500000) // 8MHz
00031  #define SPI_CLOCK_DIV1  (VARIANT_MCK/5250000)  // 16MHz
00032 
00033 RHHardwareSPI::RHHardwareSPI(Frequency frequency, BitOrder bitOrder, DataMode dataMode)
00034     :
00035     RHGenericSPI(frequency, bitOrder, dataMode)
00036 {
00037 }
00038 
00039 uint8_t RHHardwareSPI::transfer(uint8_t data) 
00040 {
00041     if (_bitOrder == BitOrderLSBFirst)
00042         data = REVERSE_BITS(data);
00043     
00044     return _SPI.write(data);
00045 }
00046 
00047 void RHHardwareSPI::attachInterrupt() 
00048 {
00049 // figure out how to do an interrupt thingy here
00050 }
00051 
00052 void RHHardwareSPI::detachInterrupt() 
00053 {
00054 // figure out how to do an interrupt thingy here too
00055 }
00056     
00057 void RHHardwareSPI::begin() 
00058 {
00059 
00060     uint8_t dataMode;
00061     if (_dataMode == DataMode0)
00062         dataMode = 0;
00063     else if (_dataMode == DataMode1)
00064         dataMode = 1;
00065     else if (_dataMode == DataMode2)
00066         dataMode = 2;
00067     else if (_dataMode == DataMode3)
00068         dataMode = 3;
00069 //  printf("mode %d\n", dataMode);
00070     _SPI.format(8, dataMode);
00071     
00072     int frequency;
00073     switch (_frequency)
00074     {
00075         case Frequency1MHz:
00076         default:
00077             frequency = 1000000;
00078             break;
00079     
00080         case Frequency2MHz:
00081             frequency = 2000000;
00082             break;
00083     
00084         case Frequency4MHz:
00085             frequency = 4000000;
00086             break;
00087     
00088         case Frequency8MHz:
00089             frequency = 8000000;
00090             break;
00091     
00092         case Frequency16MHz:
00093             frequency = 16000000;
00094             break;
00095     }
00096 //    printf("@%dHz\n",frequency);
00097     _SPI.frequency(frequency);
00098 
00099 }
00100 
00101 void RHHardwareSPI::end() 
00102 {
00103 }
00104 
00105 #endif
00106