SWSPI_BI.cpp

00001 /* SWSPI, Software SPI library
00002  * Copyright (c) 2012-2014, David R. Van Wagner, http://techwithdave.blogspot.com
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022  /* 
00023   * modified the software for adapt to the AD9249 ADC  ( bi directional ) with LVDS interface 
00024     
00025     
00026  */ 
00027 
00028 #include <mbed.h>
00029 #include "SWSPI_BI.h"
00030 #include "S_SCTRL_SM1_hwfunct.h"
00031 
00032 #define SWSPI_BI_SRC_VER  "1.50"
00033 
00034 /** 
00035     PARAM
00036     @misopin pointer to the input / output pin for the data communication
00037     @rdir_pin  pointer to the output pin that sets the remote LVDS buffer to read / write 
00038     @ldir_pin  pointer to the output pin that sets the local  LVDS buffer to read / write  
00039     @sclk_pin  pointer to the output pin that act as the clock signal for the interface 
00040     
00041 */
00042 SWSPI_BI::SWSPI_BI(DigitalInOut *msio_pin, DigitalOut *rdir_pin,DigitalOut *ldir_pin, DigitalOut *sclk_pin) 
00043     :getVersion( SWSPI_BI_HDR_VER , SWSPI_BI_SRC_VER , __TIME__, __DATE__)
00044 {
00045     
00046     msio = msio_pin;
00047     rdir = rdir_pin;
00048     ldir = ldir_pin;
00049     sclk = sclk_pin;
00050     set_bi_spi_mo(1, msio,ldir,rdir);
00051     
00052     format(8);
00053     frequency(500000);
00054 }
00055 
00056 SWSPI_BI::~SWSPI_BI()
00057 {
00058 }
00059 
00060 void SWSPI_BI::format( int bitsin, int modein ){
00061     bits = bitsin;
00062     mode = modein;
00063     polarity = !((modein >> 1) & 1);
00064     phase = modein & 1;
00065     sclk->write(polarity);
00066 }
00067 
00068 void SWSPI_BI::frequency(int hz)
00069 {
00070     this->freq = hz;
00071 }
00072 
00073 void  SWSPI_BI::write(unsigned int value, DigitalOut * cs, bool lastdata, int cs_pol,bool nxtrd ){
00074 
00075     // write data to output 
00076     // assumption is that the cs line was just set from high to low so that the SPI slave is in read mode 
00077         value= ~value;    
00078         set_bi_spi_mo(1,msio,ldir,rdir);        
00079         cs->write(cs_pol); 
00080         for (int bit = bits-1; bit >= 0; --bit)    {
00081             msio->write(((value >> bit) & 0x01) != 0);
00082             if(phase) {   sclk->write(!polarity);   wait(1.0/freq/2); sclk->write(polarity); 
00083                     if(!bit and nxtrd) set_bi_spi_mo(0,msio,ldir,rdir); // set already to input mode 
00084                      wait(1.0/freq/2);    }
00085             else  { wait(1.0/freq/2);  sclk->write(!polarity);  wait(1.0/freq/2);  sclk->write(polarity);      }
00086           
00087           
00088         }
00089         if( lastdata) {
00090             set_bi_spi_mo(0,msio,ldir,rdir); 
00091             cs->write(!cs_pol); 
00092         }
00093         else {
00094         }
00095 }        
00096 
00097 unsigned int  SWSPI_BI::read( DigitalOut * cs, bool lastdata, int cs_pol ){
00098     unsigned int read = 0;    
00099     set_bi_spi_mo(0,msio,ldir,rdir);        
00100     cs->write(cs_pol); 
00101     wait(1.0/freq/2);
00102     for (int bit = bits-1; bit >= 0; --bit)  {
00103         if (phase == 0) {
00104             if (msio->read())  read |= (1 << bit);
00105                
00106         }
00107         sclk->write(!polarity);
00108         wait(1.0/freq/2);
00109         if (phase == 1) {
00110             if (msio->read()) read |= (1 << bit);            
00111         }
00112 
00113         sclk->write(polarity);
00114         wait(1.0/freq/2);
00115     }
00116     if( lastdata) {    
00117             cs->write(!cs_pol); 
00118     }
00119     // else keep current io config 
00120    
00121     
00122     return ~read;
00123 }
00124