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/* -*- 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 3, 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., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "microtune_4937.h"
#include <stdlib.h>
#include <stdio.h>
#include <i2c.h>
static const double first_IF = 43.75e6;
// The tuner internally has 3 bands: VHF Low, VHF High & UHF.
// These are the recommened boundaries
static const double VHF_High_takeover = 158e6;
static const double UHF_takeover = 464e6;
static unsigned char
control_byte_1 (bool fast_tuning_p, int reference_divisor)
{
int c = 0x88;
if (fast_tuning_p)
c |= 0x40;
switch (reference_divisor){
case 512:
c |= 0x3 << 1; break;
case 640:
c |= 0x0 << 1; break;
case 1024:
c |= 0x1 << 1; break;
default:
abort ();
}
return c;
}
static unsigned char
control_byte_2 (double target_freq, bool shutdown_tx_PGA)
{
int c;
if (target_freq < VHF_High_takeover) // VHF low
c = 0xa0;
else if (target_freq < UHF_takeover) // VHF high
c = 0x90;
else // UHF
c = 0x30;
if (shutdown_tx_PGA)
c |= 0x08;
return c;
}
microtune_4937::microtune_4937 (i2c_sptr i2c, int i2c_addr)
{
d_i2c = i2c;
d_i2c_addr = i2c_addr;
d_reference_divider = 640;
d_fast_tuning_p = false;
}
microtune_4937::~microtune_4937 ()
{
// nop
}
/*!
* \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
microtune_4937::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;
// f_osc = f_ref * 8 * divisor
// divisor = f_osc / (f_ref * 8)
int divisor = (int) ((target_f_osc + (f_ref * 4)) / (f_ref * 8));
double actual_freq = (f_ref * 8 * divisor) - first_IF;
if (p_actual_freq != 0)
*p_actual_freq = actual_freq;
if ((divisor & ~0x7fff) != 0) // 15 bit divisor
return false;
buf[0] = (divisor >> 8) & 0xff; // DB1
buf[1] = divisor & 0xff; // DB2
buf[2] = control_byte_1 (d_fast_tuning_p, d_reference_divider);
buf[3] = control_byte_2 (target_freq, true);
#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 d_i2c->write (d_i2c_addr, buf, 4);
}
/*!
* \returns true iff PLL is locked
*/
bool
microtune_4937::pll_locked_p ()
{
// FIXME
return true;
}
/*!
* \returns the output frequency of the tuner in Hz.
*/
double
microtune_4937::get_output_freq ()
{
return 5.75e6; // 3x7702
}
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