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microtune_4702.cc

/* -*- c++-*- */
/*
 * Copyright 2001,2003 Free Software Foundation, Inc.
 * 
 * This file is part of GNU Radio
 *
 * GNU Radio 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 2, or (at your option)
 * any later version.
 *
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "microtune_4702.h"
#include <stdlib.h>
#include <stdio.h>

static const double first_IF = 36.00e6;

// The tuner internally has 3 bands: VHF Low, VHF High & UHF.
// These are the recommened boundaries
static const double VHF_High_takeover = 174e6;
static const double UHF_takeover = 470e6;

static int PLL_I2C_ADDR     =       0x60;

static unsigned char
control_byte_1 (bool prescaler, int reference_divisor)
{
  int c = 0x80;
  //Note: Last two divider bits (bits 2 and 3 of this byte) determined later
  if (prescaler)
    c |= 0x10;

  switch (reference_divisor){
  case 2:
    c |= 0x00;    break;
  case 4:
    c |= 0x01;    break;
  case 8:
    c |= 0x02;    break;
  case 16:
    c |= 0x03;    break;
  case 32:
    c |= 0x04;    break;
  case 64:
    c |= 0x05;    break;
  case 128:
    c |= 0x06;    break;
  case 256:
    c |= 0x07;    break;
  case 24:
    c |= 0x08;    break;
  case 5:
    c |= 0x09;    break;
  case 10:
    c |= 0x0A;    break;
  case 20:
    c |= 0x0B;    break;
  case 40:
    c |= 0x0C;    break;
  case 80:
    c |= 0x0D;    break;
  case 160:
    c |= 0x0E;    break;
  case 320:
    c |= 0x0F;    break;
  default:
    abort ();
  }
  return c;
}

static unsigned char
control_byte_2 (double target_freq)
{
  int c;

  if (target_freq < VHF_High_takeover)    // VHF low
    c = 0x8E;
  else if (target_freq < UHF_takeover)    // VHF high
  {
    c = 0x05;
      if (target_freq < 390e6)
            c |= 0x40;
      else
            c |= 0x80;
  }
  else
  {                           // UHF
    c = 0x03;
      if (target_freq < 750e6)
            c |= 0x80;
      else
            c |= 0xC0;
  }

  return c;
}


/*!
 * \brief select RF frequency to be tuned to output frequency.
 * \p target_freq is the requested frequency in Hz, \p actual_freq
 * is set to the actual frequency tuned.  It takes about 100 ms
 * for the PLL to settle.
 *
 * \returns true iff sucessful.
 */
bool
00120 microtune_4702::set_RF_freq (double target_freq, double *p_actual_freq)
{
  unsigned char buf[4];

  double target_f_osc = target_freq + first_IF;

  double f_ref = 4e6 / d_reference_divider;

  //int divisor = (int) ((target_f_osc + (f_ref * 4)) / (f_ref * 8));

  long int divisor = (long int) (target_f_osc / f_ref);
  double actual_freq = (f_ref * divisor) - first_IF;
  if (p_actual_freq != 0)
    *p_actual_freq = actual_freq;

  if ((divisor & ~0x1ffff) != 0)    // >17 bit divisor
    return false;

  buf[0] = ((divisor & 0x07f00) >> 8) & 0xff;   // DB1
  buf[1] = divisor & 0xff;          // DB2
  buf[2] = control_byte_1 (prescaler, d_reference_divider);
  buf[2] = (buf[2]|(((divisor & 0x18000) >> 10)) & 0xff);
  buf[3] = control_byte_2 (target_freq);

  printf ("%x\n", PLL_I2C_ADDR);
//#if 0
  printf ("set_RF_freq: target: %g MHz actual: %g MHz %02x %02x %02x %02x\n",
        target_freq/1e6, actual_freq/1e6, buf[0], buf[1], buf[2], buf[3]);
//#endif

  return i2c_write (PLL_I2C_ADDR, buf, sizeof (buf));
}


bool
microtune_4702::read_info (unsigned char* buf)
{
        return i2c_write (PLL_I2C_ADDR, buf, 2);
}

/*!
 * \returns true iff PLL is locked
 */
bool 
00164 microtune_4702::pll_locked_p ()
{
  // FIXME
  return true;
}

/*!
 * \returns the output frequency of the tuner in Hz.
 */
double
00174 microtune_4702::get_output_freq ()
{
  return 36.00e6;
}

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