Receive.c

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/********************************************************************************/
/* Use a raspberry pi with a IR led as remote control for your Tv, Dvd etc.     */
/* Copyright (C) 2016  Ed Kapitein                                              */
/*                                                                              */
/* This program is free software: you can redistribute it and/or modify         */
/* it under the terms of the GNU General Public License as published by         */
/* the Free Software Foundation, either version 3 of the License, or            */
/* (at your option) any later version.                                          */
/*                                                                              */
/* This program is distributed in the hope that it will be useful,              */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of               */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                */
/* GNU General Public License for more details.                                 */
/*                                                                              */
/* You should have received a copy of the GNU General Public License            */
/* along with this program.  If not, see <http://www.gnu.org/licenses/>.        */
/********************************************************************************/
#define _POSIX_C_SOURCE 199309L
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <inttypes.h>
#include <time.h>
#include <sys/timeb.h>
/* #include "../Receive/Receive.h" */
 
#define BCM2708_PERI_BASE       0x20000000
#define GPIO                    0x00200000 /* GPIO controller */
#define TIMER_CONTROL           0x00003000
#define ONE_MHZ_COUNTER         0x00000004

#define PAGE_SIZE (4*1024)
#define BLOCK_SIZE (4*1024)
 
 
#define INP_GPIO(g) *(gpio+((g)/10)) &= ~(7<<(((g)%10)*3))
#define OUT_GPIO(g) *(gpio+((g)/10)) |=  (1<<(((g)%10)*3))
#define SET_GPIO_ALT(g,a) *(gpio+(((g)/10))) |= (((a)<=3?(a)+4:(a)==4?3:2)<<(((g)%10)*3))
 
#define GPIO_SET *(gpio+7)
#define GPIO_CLR *(gpio+10)
 
#define GET_GPIO(g) (*(gpio+13)&(1<<g))
 
#define GPIO_PULL *(gpio+37)
#define GPIO_PULLCLK0 *(gpio+38)
 
int main()
 {
 #define NrOfSamples 500
 long int               i;
 uint32_t               Buffer[NrOfSamples + 1];
 uint32_t               TimeStamp[NrOfSamples + 1];
 void                   *TimerBase;
 volatile uint32_t      *gpio;
 volatile uint32_t      *Timer;
 uint32_t               StartTime;
 int                    fd;

 /* open /dev/mem */
 if ((fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0)
  {
  printf("can't open /dev/mem \n");
  exit(-1);
  }

 /* set a pointer to the 1MHz clock we use for time stamps */
 if( ( TimerBase = mmap( NULL, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, BCM2708_PERI_BASE + TIMER_CONTROL ) ) == NULL )
  {
  fprintf( stderr, "201608281433 mmap() failed.\n");
  return -1;
  }
 Timer = (uint32_t *)((char *)TimerBase + ONE_MHZ_COUNTER );

 /* set a pointer to the gpio base */
 if( ( gpio = mmap( NULL, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, BCM2708_PERI_BASE + GPIO ) ) == NULL )
  {
  fprintf( stderr, "201608281434 mmap() failed.\n");
  return -1;
  }

 INP_GPIO(17); 

 while( GET_GPIO(17) ); /* wait for the pulse */
 StartTime = *Timer;

 for(i=0; i< NrOfSamples; i++)  /* sample as fast as we can */
  {
  Buffer[i] = GET_GPIO(17);
  while( Buffer[i] == GET_GPIO(17) )
   {
   TimeStamp[i] = *Timer - StartTime;
   }
  }

 printf("0,1\n");
 for(i=0; i< NrOfSamples; i++ ) /* print out the samples */
  {
  printf( "%" PRIu32 ",", TimeStamp[i] );
  if(Buffer[i])
   {
   printf( "1\n" );     /* the carrier was off, but has switched on after this timestamp */
   }
  else
   {
   printf( "0\n" );     /* the carrier was on, but has switched off after this timestamp */
   }
  }

 return(0);

 }