temp-fan-control/gertboard_sw/atod.c

//
// Gertboard Demo
//
// SPI (ADC/DAC) control code
//
// This code is part of the Gertboard test suite
//
//
// Copyright (C) Gert Jan van Loo & Myra VanInwegen 2012
// No rights reserved
// You may treat this program as if it was in the public domain
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
//
// Try to strike a balance between keep code simple for
// novice programmers but still have reasonable quality code
//

#include "gb_common.h"
#include "gb_spi.h"
#include <time.h>
// Set GPIO pins to the right mode
// DEMO GPIO mapping:
//         Function            Mode
// GPIO0=  unused
// GPIO1=  unused
// GPIO4=  unused
// GPIO7=  unused
// GPIO8=  SPI chip select A   Alt. 0
// GPIO9=  SPI MISO            Alt. 0
// GPIO10= SPI MOSI            Alt. 0
// GPIO11= SPI CLK             Alt. 0
// GPIO14= unused
// GPIO15= unused
// GPIO17= unused
// GPIO18= unused
// GPIO21= unused
// GPIO22= unused
// GPIO23= unused
// GPIO24= unused
// GPIO25= unused
//

// For A to D we only need the SPI bus and SPI chip select A
void setup_gpio()
{
   INP_GPIO(8);  SET_GPIO_ALT(8,0);
   INP_GPIO(9);  SET_GPIO_ALT(9,0);
   INP_GPIO(10); SET_GPIO_ALT(10,0);
   INP_GPIO(11); SET_GPIO_ALT(11,0);
} // setup_gpio


//
//  Read ADC input 0 and show as horizontal bar
//
void main(void)
{ int r, v, s, i, chan;

  do {
    printf ("Which channel do you want to test? Type 0 or 1.\n");
    chan  = (int) getchar();
    (void) getchar(); // eat carriage return
  } while (chan != '0' && chan != '1');
  chan = chan - '0';

  printf ("These are the connections for the analogue to digital test:\n");
  printf ("jumper connecting GP11 to SCLK\n");
  printf ("jumper connecting GP10 to MOSI\n");
  printf ("jumper connecting GP9 to MISO\n");
  printf ("jumper connecting GP8 to CSnA\n");
  printf ("Potentiometer connections:\n");
  printf ("  (call 1 and 3 the ends of the resistor and 2 the wiper)\n");
  printf ("  connect 3 to 3V3\n");
  printf ("  connect 2 to AD%d\n", chan);
  printf ("  connect 1 to GND\n");
  printf ("When ready hit enter.\n");
  (void) getchar();

  // Map the I/O sections
  setup_io();

  // activate SPI bus pins
  setup_gpio();

  // Setup SPI bus
  setup_spi();

  // The value returned by the A to D can jump around quite a bit, so 
  // simply printing out the value isn't very useful. The bar graph
  // is better because this hides the noise in the signal.

  clock_t t,f;

//  for (r=0; r<100000; r++)
  while(1)
  {
    v= read_adc(chan);
    // V should be in range 0-1023
    // map to 0-63
    //s = v >> 4;
    //printf("%04d;%f;%d\n",v,((float)f)/CLOCKS_PER_SEC,f);
	printf("%d %d     %f     %f     ",v,v/2,(v/2)*2.54,v*(6.45/512));
    /*/ show horizontal bar
    for (i = 0; i < s; i++)
      putchar('#');
    for (i = 0; i < 64 - s; i++)
      putchar(' ');*/
	putchar(0x0D); // go to start of the line*/
    short_wait();
  } // repeated read

  printf("\n");
  restore_io();
} // main