path: root/usrp/host/lib/db_xcvr2450.cc

//
// Copyright 2008,2009 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 asversion 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 <usrp/db_xcvr2450.h>
#include <db_base_impl.h>
#include <cmath>
#include <boost/thread.hpp>
#include <boost/weak_ptr.hpp>
#include <cstdio>

#if 0
#define LO_OFFSET 4.25e6
#else
#define LO_OFFSET 0
#define NO_LO_OFFSET
#endif


/* ------------------------------------------------------------------------
 *  A few comments about the XCVR2450:
 *
 * It is half-duplex.  I.e., transmit and receive are mutually exclusive.
 * There is a single LO for both the Tx and Rx sides.
 * For our purposes the board is always either receiving or transmitting.
 *
 * Each board is uniquely identified by the *USRP hardware* instance and side
 * This dictionary holds a weak reference to existing board controller so it
 * can be created or retrieved as needed.
 */



// TX IO Pins
#define HB_PA_OFF      (1 << 15)    // 5GHz PA, 1 = off, 0 = on
#define LB_PA_OFF      (1 << 14)    // 2.4GHz PA, 1 = off, 0 = on
#define ANTSEL_TX1_RX2 (1 << 13)    // 1 = Ant 1 to TX, Ant 2 to RX
#define ANTSEL_TX2_RX1 (1 << 12)    // 1 = Ant 2 to TX, Ant 1 to RX
#define TX_EN          (1 << 11)    // 1 = TX on, 0 = TX off
#define AD9515DIV      (1 << 4)     // 1 = Div  by 3, 0 = Div by 2

#define TX_OE_MASK HB_PA_OFF|LB_PA_OFF|ANTSEL_TX1_RX2|ANTSEL_TX2_RX1|TX_EN|AD9515DIV
#define TX_SAFE_IO HB_PA_OFF|LB_PA_OFF|ANTSEL_TX1_RX2|AD9515DIV

// RX IO Pins
#define LOCKDET (1 << 15)           // This is an INPUT!!!
#define EN      (1 << 14)
#define RX_EN   (1 << 13)           // 1 = RX on, 0 = RX off
#define RX_HP   (1 << 12)
#define RX_OE_MASK EN|RX_EN|RX_HP
#define RX_SAFE_IO EN

struct xcvr2450_key {
  std::string serial_no;
  int which;

  bool operator==(const xcvr2450_key &x){
    return x.serial_no ==serial_no && x.which == which;
  }
};

class xcvr2450
{
private:
  usrp_basic *d_raw_usrp;
  int d_which;

  bool d_is_shutdown;
  int d_spi_format, d_spi_enable;
  
  int d_mimo, d_int_div, d_frac_div, d_highband, d_five_gig;
  int d_cp_current, d_ref_div, d_rssi_hbw;
  int d_txlpf_bw, d_rxlpf_bw, d_rxlpf_fine, d_rxvga_ser;
  int d_rssi_range, d_rssi_mode, d_rssi_mux;
  int d_rx_hp_pin, d_rx_hpf, d_rx_ant;
  int d_tx_ant, d_txvga_ser, d_tx_driver_lin;
  int d_tx_vga_lin, d_tx_upconv_lin, d_tx_bb_gain;
  int d_pabias_delay, d_pabias, rx_rf_gain, rx_bb_gain, d_txgain;
  int d_rx_rf_gain, d_rx_bb_gain;

  int d_reg_standby, d_reg_int_divider, d_reg_frac_divider, d_reg_bandselpll;
  int d_reg_cal, dsend_reg, d_reg_lpf, d_reg_rxrssi_ctrl, d_reg_txlin_gain;
  int d_reg_pabias, d_reg_rxgain, d_reg_txgain;

  int d_ad9515_div;

  void _set_rfagc(float gain);
  void _set_ifagc(float gain);
  void _set_pga(float pga_gain);

public:
  usrp_basic *usrp(){
    return d_raw_usrp;
  }

  xcvr2450(usrp_basic_sptr usrp, int which);
  ~xcvr2450();
  void shutdown();

  void set_reg_standby();
  
  // Integer-Divider Ratio (3)
  void set_reg_int_divider();
  
  // Fractional-Divider Ratio (4)
  void set_reg_frac_divider();
  
  // Band Select and PLL (5)
  void set_reg_bandselpll();
  
  // Calibration (6)
  void set_reg_cal();

  // Lowpass Filter (7)
  void set_reg_lpf();
  
  // Rx Control/RSSI (8)
  void set_reg_rxrssi_ctrl();
  
  // Tx Linearity/Baseband Gain (9)
  void set_reg_txlin_gain();
  
  // PA Bias DAC (10)
  void set_reg_pabias();
  
  // Rx Gain (11)
  void set_reg_rxgain();
  
  // Tx Gain (12)
  void set_reg_txgain();
  
  // Send register write to SPI
  void send_reg(int v);

  void set_gpio();
  bool lock_detect();
  bool set_rx_gain(float gain);
  bool set_tx_gain(float gain);

  struct freq_result_t set_freq(double target_freq);
};


/*****************************************************************************/


xcvr2450::xcvr2450(usrp_basic_sptr _usrp, int which)
  : d_raw_usrp(_usrp.get()), d_which(which), d_is_shutdown(false)
{
  // Handler for Tv Rx daughterboards.
  // 
  // @param usrp: instance of usrp.source_c
  // @param which: which side: 0, 1 corresponding to RX_A or RX_B respectively

  // Use MSB with no header
  d_spi_format = SPI_FMT_MSB | SPI_FMT_HDR_0;

  if(which == 0) {
    d_spi_enable = SPI_ENABLE_RX_A;
  }
  else {
    d_spi_enable = SPI_ENABLE_RX_B;
  }

  // Sane defaults
  d_mimo = 1;          // 0 = OFF, 1 = ON
  d_int_div = 192;     // 128 = min, 255 = max
  d_frac_div = 0;      // 0 = min, 65535 = max
  d_highband = 0;      // 0 = freq <= 5.4e9, 1 = freq > 5.4e9
  d_five_gig = 0;      // 0 = freq <= 3.e9, 1 = freq > 3e9
  d_cp_current = 1;    // 0 = 2mA, 1 = 4mA
  d_ref_div = 1;       // 1 to 7
  d_rssi_hbw = 0;      // 0 = 2 MHz, 1 = 6 MHz
  d_txlpf_bw = 1;      // 1 = 12 MHz, 2 = 18 MHz, 3 = 24 MHz
  d_rxlpf_bw = 1;      // 0 = 7.5 MHz, 1 = 9.5 MHz, 2 = 14 MHz, 3 = 18 MHz
  d_rxlpf_fine = 2;    // 0 = 90%, 1 = 95%, 2 = 100%, 3 = 105%, 4 = 110%
  d_rxvga_ser = 1;     // 0 = RXVGA controlled by B7:1, 1=controlled serially
  d_rssi_range = 1;    // 0 = low range (datasheet typo), 1=high range (0.5V - 2.0V) 
  d_rssi_mode = 1;     // 0 = enable follows RXHP, 1 = enabled
  d_rssi_mux = 0;      // 0 = RSSI, 1 = TEMP
  d_rx_hp_pin = 0;     // 0 = Fc set by rx_hpf, 1 = 600 KHz
  d_rx_hpf = 0;        // 0 = 100Hz, 1 = 30KHz
  d_rx_ant = 0;        // 0 = Ant. #1, 1 = Ant. #2
  d_tx_ant = 0;        // 0 = Ant. #1, 1 = Ant. #2
  d_txvga_ser = 1;     // 0 = TXVGA controlled by B6:1, 1=controlled serially
  d_tx_driver_lin = 2; // 0=50% (worst linearity), 1=63%, 2=78%, 3=100% (best lin)
  d_tx_vga_lin = 2;    // 0=50% (worst linearity), 1=63%, 2=78%, 3=100% (best lin)
  d_tx_upconv_lin = 2; // 0=50% (worst linearity), 1=63%, 2=78%, 3=100% (best lin)
  d_tx_bb_gain = 3;    // 0=maxgain-5dB, 1=max-3dB, 2=max-1.5dB, 3=max
  d_pabias_delay = 15; // 0 = 0, 15 = 7uS
  d_pabias = 0;        // 0 = 0 uA, 63 = 315uA
  d_rx_rf_gain = 0;    // 0 = 0dB, 1 = 0dB, 2 = 15dB, 3 = 30dB
  d_rx_bb_gain = 16;   // 0 = min, 31 = max (0 - 62 dB)

  d_txgain = 63;       // 0 = min, 63 = max

  // Initialize GPIO and ATR  
  usrp()->common_write_io(C_TX, d_which, TX_SAFE_IO, TX_OE_MASK);
  usrp()->_common_write_oe(C_TX, d_which, TX_OE_MASK, 0xffff);
  usrp()->common_write_atr_txval(C_TX, d_which, TX_SAFE_IO);
  usrp()->common_write_atr_rxval(C_TX, d_which, TX_SAFE_IO);
  usrp()->common_write_atr_mask(C_TX, d_which, TX_OE_MASK);

  usrp()->common_write_io(C_RX, d_which, RX_SAFE_IO, RX_OE_MASK);
  usrp()->_common_write_oe(C_RX, d_which, RX_OE_MASK, 0xffff);
  usrp()->common_write_atr_txval(C_RX, d_which, RX_SAFE_IO);
  usrp()->common_write_atr_rxval(C_RX, d_which, RX_SAFE_IO);
  usrp()->common_write_atr_mask(C_RX, d_which, RX_OE_MASK);

  // Initialize chipset
  // TODO: perform reset sequence to ensure power up defaults
  set_reg_standby();
  set_reg_bandselpll();
  set_reg_cal();
  set_reg_lpf();
  set_reg_rxrssi_ctrl();
  set_reg_txlin_gain();
  set_reg_pabias();
  set_reg_rxgain();
  set_reg_txgain();
  //FIXME: set_freq(2.45e9);
}

xcvr2450::~xcvr2450()
{
  //printf("xcvr2450::destructor\n");
  shutdown();
}

void
xcvr2450::shutdown()
{
  if (!d_is_shutdown){
    d_is_shutdown = true;
    usrp()->common_write_atr_txval(C_TX, d_which, TX_SAFE_IO);
    usrp()->common_write_atr_rxval(C_TX, d_which, TX_SAFE_IO);
    usrp()->common_write_atr_txval(C_RX, d_which, RX_SAFE_IO);
    usrp()->common_write_atr_rxval(C_RX, d_which, RX_SAFE_IO);
  }
}


void
xcvr2450::set_reg_standby()
{
  d_reg_standby = ((d_mimo<<17) | 
		   (1<<16)      | 
		   (1<<6)       | 
		   (1<<5)       | 
		   (1<<4)       | 2);
  send_reg(d_reg_standby);
}

void
xcvr2450::set_reg_int_divider()
{
  d_reg_int_divider = (((d_frac_div & 0x03)<<16) | 
		       (d_int_div<<4)            | 3);
  send_reg(d_reg_int_divider);
}

void
xcvr2450::set_reg_frac_divider()
{
  d_reg_frac_divider = ((d_frac_div & 0xfffc)<<2) | 4;
  send_reg(d_reg_frac_divider);
}
        
void
xcvr2450::set_reg_bandselpll()
{
  d_reg_bandselpll = ((d_mimo<<17)      |
		      (1<<16)           |
		      (1<<15)           |
		      (0<<11)           |
		      (d_highband<<10)  |
		      (d_cp_current<<9) |
		      (d_ref_div<<5)    |
		      (d_five_gig<<4)   | 5);
  send_reg(d_reg_bandselpll);
  d_reg_bandselpll = ((d_mimo<<17)      |
		      (1<<16)           |
		      (1<<15)           |
		      (1<<11)           |
		      (d_highband<<10)  |
		      (d_cp_current<<9) |
		      (d_ref_div<<5)    |
		      (d_five_gig<<4)   | 5);
  send_reg(d_reg_bandselpll);
}
     
void
xcvr2450::set_reg_cal()
{
  // FIXME do calibration
  d_reg_cal = (1<<14)|6;
  send_reg(d_reg_cal);
}

void
xcvr2450::set_reg_lpf()
{
  d_reg_lpf = (
	     (d_rssi_hbw<<15)  |
	     (d_txlpf_bw<<10)  |
	     (d_rxlpf_bw<<9)   |
	     (d_rxlpf_fine<<4) | 7);
  send_reg(d_reg_lpf);
}

void
xcvr2450::set_reg_rxrssi_ctrl()
{
  d_reg_rxrssi_ctrl = ((d_rxvga_ser<<16)  |
		       (d_rssi_range<<15) |
		       (d_rssi_mode<<14)  |
		       (d_rssi_mux<<12)   |
		       (1<<9)             |
		       (d_rx_hpf<<6)      |
		       (1<<4) 		  | 8);
  send_reg(d_reg_rxrssi_ctrl);
}

void
xcvr2450::set_reg_txlin_gain()
{
  d_reg_txlin_gain = ((d_txvga_ser<<14)     |
		      (d_tx_driver_lin<<12) |
		      (d_tx_vga_lin<<10)    |
		      (d_tx_upconv_lin<<6)  |
		      (d_tx_bb_gain<<4)     | 9);
  send_reg(d_reg_txlin_gain);
}

void
xcvr2450::set_reg_pabias()
{
  d_reg_pabias = (
		  (d_pabias_delay<<10) |
		  (d_pabias<<4)        | 10);
  send_reg(d_reg_pabias);
}

void
xcvr2450::set_reg_rxgain()
{
  d_reg_rxgain = (
		  (d_rx_rf_gain<<9) |
		  (d_rx_bb_gain<<4) | 11);
  send_reg(d_reg_rxgain);
}

void
xcvr2450::set_reg_txgain()
{
  d_reg_txgain = (d_txgain<<4) | 12;
  send_reg(d_reg_txgain);
}

void
xcvr2450::send_reg(int v)
{
  // Send 24 bits, it keeps last 18 clocked in
  char c[3];
  c[0] = (char)((v >> 16) & 0xff);
  c[1] = (char)((v >>  8) & 0xff);
  c[2] = (char)((v & 0xff));
  std::string s(c, 3);
  
  usrp()->_write_spi(0, d_spi_enable, d_spi_format, s);
  //printf("xcvr2450: Setting reg %d to %X\n", (v&15), v);
}

// ----------------------------------------------------------------

void
xcvr2450::set_gpio()
{
  // We calculate four values:
  //
  // io_rx_while_rx: what to drive onto io_rx_* when receiving
  // io_rx_while_tx: what to drive onto io_rx_* when transmitting
  // io_tx_while_rx: what to drive onto io_tx_* when receiving
  // io_tx_while_tx: what to drive onto io_tx_* when transmitting
  //
  // B1-B7 is ignored as gain is set serially for now.
  
  int rx_hp, tx_antsel, rx_antsel, tx_pa_sel;
  if(d_rx_hp_pin)
    rx_hp = RX_HP;
  else
    rx_hp = 0;
  
  if(d_tx_ant)
    tx_antsel = ANTSEL_TX2_RX1;
  else
    tx_antsel = ANTSEL_TX1_RX2;

  if(d_rx_ant)
    rx_antsel = ANTSEL_TX2_RX1;
  else
    rx_antsel = ANTSEL_TX1_RX2;

  if(d_five_gig)
    tx_pa_sel = LB_PA_OFF;
  else
    tx_pa_sel = HB_PA_OFF;
 
  // Reset GPIO and ATR
  // FIXME: dont set io, oe, atr mask once basic code stops overriding our settings
  usrp()->common_write_io(C_TX, d_which, TX_SAFE_IO, TX_OE_MASK);
  usrp()->_common_write_oe(C_TX, d_which, TX_OE_MASK, 0xffff);
  usrp()->common_write_atr_txval(C_TX, d_which, tx_pa_sel|tx_antsel|TX_EN|AD9515DIV);
  usrp()->common_write_atr_rxval(C_TX, d_which, HB_PA_OFF|LB_PA_OFF|rx_antsel|AD9515DIV);
  usrp()->common_write_atr_mask(C_TX, d_which, TX_OE_MASK);

  usrp()->common_write_io(C_RX, d_which, RX_SAFE_IO, RX_OE_MASK);
  usrp()->_common_write_oe(C_RX, d_which, RX_OE_MASK, 0xffff);
  usrp()->common_write_atr_txval(C_RX, d_which, EN|rx_hp);
  usrp()->common_write_atr_rxval(C_RX, d_which, EN|rx_hp|RX_EN);
  usrp()->common_write_atr_mask(C_RX, d_which, RX_OE_MASK);

  //printf("GPIO: RXRX=%04X RXTX=%04X TXRX=%04X TXTX=%04X\n",
  //       io_rx_while_rx, io_rx_while_tx, io_tx_while_rx, io_tx_while_tx);
}
  

struct freq_result_t
xcvr2450::set_freq(double target_freq)
{
  struct freq_result_t args = {false, 0};

  double scaler;

  if(target_freq > 3e9) {
    d_five_gig = 1;
    d_ad9515_div = 3;
    scaler = 4.0/5.0;
  }
  else {
    d_five_gig = 0;
    d_ad9515_div = 3;
    scaler = 4.0/3.0;
  }

  if(target_freq > 5.408e9) {
    d_highband = 1;
  }
  else {
    d_highband = 0;
  }

  double vco_freq = target_freq*scaler;
  double sys_clk = usrp()->fpga_master_clock_freq();  // Usually 64e6 
  double ref_clk = sys_clk / d_ad9515_div;
        
  double phdet_freq = ref_clk/d_ref_div;
  double div = vco_freq/phdet_freq;
  d_int_div = int(floor(div));
  d_frac_div = int((div-d_int_div)*65536.0);
  // double actual_freq = phdet_freq*(d_int_div+(d_frac_div/65536.0))/scaler;
  
  //printf("RF=%f VCO=%f R=%d PHD=%f DIV=%3.5f I=%3d F=%5d ACT=%f\n",
  //	 target_freq, vco_freq, d_ref_div, phdet_freq,
  //	 div, d_int_div, d_frac_div, actual_freq);

  set_gpio();
  set_reg_int_divider();
  set_reg_frac_divider();
  set_reg_bandselpll();

  args.ok = lock_detect();
#ifdef NO_LO_OFFSET
  args.baseband_freq = target_freq;
#else
  args.baseband_freq = actual_freq;
#endif

  if(!args.ok){
    printf("Fail %f\n", target_freq);
  }
  return args;
}

bool
xcvr2450::lock_detect()
{
  /*
    @returns: the value of the VCO/PLL lock detect bit.
    @rtype: 0 or 1
  */
  if(usrp()->common_read_io(C_RX, d_which) & LOCKDET) {
    return true;
  }
  else {      // Give it a second chance
    if(usrp()->common_read_io(C_RX, d_which) & LOCKDET)
      return true;
    else
      return false;
  }
}

bool
xcvr2450::set_rx_gain(float gain)
{
  if(gain < 0.0) 
    gain = 0.0;
  if(gain > 92.0)
    gain = 92.0;

  // Split the gain between RF and baseband
  // This is experimental, not prescribed
  if(gain < 31.0) {
    d_rx_rf_gain = 0;		           // 0 dB RF gain
    rx_bb_gain = int(gain/2.0);
  }
  
  if(gain >= 30.0 and gain < 60.5) {
    d_rx_rf_gain = 2;                    // 15 dB RF gain
    d_rx_bb_gain = int((gain-15.0)/2.0);
  }
  
  if(gain >= 60.5) {
    d_rx_rf_gain = 3;			   // 30.5 dB RF gain
    d_rx_bb_gain = int((gain-30.5)/2.0);
  }
  
  set_reg_rxgain();
  
  return true;
}

bool
xcvr2450::set_tx_gain(float gain)
{
  if(gain < 0.0) {
    gain = 0.0;
  }
  if(gain > 30.0) {
    gain = 30.0;
  }
  
  d_txgain = int((gain/30.0)*63);
  set_reg_txgain();

  return true;
}


/*****************************************************************************/


struct xcvr2450_table_entry {
  xcvr2450_key 			key;
  boost::weak_ptr<xcvr2450>	value;

  xcvr2450_table_entry(const xcvr2450_key &_key, boost::weak_ptr<xcvr2450> _value)
    : key(_key), value(_value) {}
};

typedef std::vector<xcvr2450_table_entry> xcvr2450_table;

static boost::mutex s_table_mutex;
static xcvr2450_table s_table;

static xcvr2450_sptr
_get_or_make_xcvr2450(usrp_basic_sptr usrp, int which)
{
  xcvr2450_key key = {usrp->serial_number(), which};

  boost::mutex::scoped_lock	guard(s_table_mutex);

  for (xcvr2450_table::iterator p = s_table.begin(); p != s_table.end();){
    if (p->value.expired())	// weak pointer is now dead
      p = s_table.erase(p);	// erase it
    else {
      if (key == p->key){	// found it
	return xcvr2450_sptr(p->value);
      }
      else		        
	++p;			// keep looking
    }
  }

  // We don't have the xcvr2450 we're looking for

  // create a new one and stick it in the table.
  xcvr2450_sptr r(new xcvr2450(usrp, which));
  xcvr2450_table_entry t(key, r);
  s_table.push_back(t);

  return r;
}


/*****************************************************************************/


db_xcvr2450_base::db_xcvr2450_base(usrp_basic_sptr usrp, int which)
  : db_base(usrp, which)
{
  /*
   * Abstract base class for all xcvr2450 boards.
   * 
   * Derive board specific subclasses from db_xcvr2450_base_{tx,rx}
   *
   * @param usrp: instance of usrp.source_c
   * @param which: which side: 0 or 1 corresponding to side A or B respectively
   * @type which: int
   */
  
  d_xcvr = _get_or_make_xcvr2450(usrp, which);
}

db_xcvr2450_base::~db_xcvr2450_base()
{
}

void
db_xcvr2450_base::shutdown_common()
{
  // If the usrp_basic in the xcvr2450 is the same as the usrp_basic
  // in the daughterboard, shutdown the xcvr now (when only one of Tx
  // and Rx is open, this is always true).

  if (d_xcvr->usrp() == usrp()){
    //std::cerr << "db_xcvr2450_base::shutdown_common: same -> shutting down\n";
    d_xcvr->shutdown();
  }
  else {
    //std::cerr << "db_xcvr2450_base::shutdown_common: different -> ignoring\n";
  }
}

struct freq_result_t
db_xcvr2450_base::set_freq(double target_freq)
{
  /*
   * @returns (ok, actual_baseband_freq) where:
   * ok is True or False and indicates success or failure,
   * actual_baseband_freq is the RF frequency that corresponds to DC in the IF.
   */
  return d_xcvr->set_freq(target_freq+d_lo_offset);
}

bool
db_xcvr2450_base::is_quadrature()
{
  /*
   * Return True if this board requires both I & Q analog channels.
   *
   * This bit of info is useful when setting up the USRP Rx mux register.
   */
   return true;
}

double
db_xcvr2450_base::freq_min()
{
  return 2.4e9;
}

double
db_xcvr2450_base::freq_max()
{
  return 6.0e9;
}


/******************************************************************************/


db_xcvr2450_tx::db_xcvr2450_tx(usrp_basic_sptr usrp, int which)
  : db_xcvr2450_base(usrp, which)
{
  set_lo_offset(LO_OFFSET);
  //printf("db_xcvr2450_tx::db_xcvr2450_tx\n");
}

db_xcvr2450_tx::~db_xcvr2450_tx()
{
  shutdown();
}

void
db_xcvr2450_tx::shutdown()
{
  if (!d_is_shutdown){
    d_is_shutdown = true;
    shutdown_common();
  }
}

float
db_xcvr2450_tx::gain_min()
{
  return 0;
}

float
db_xcvr2450_tx::gain_max()
{
  return 30;
}

float
db_xcvr2450_tx::gain_db_per_step()
{
  return (30.0/63.0);
}

bool
db_xcvr2450_tx::set_gain(float gain)
{
  return d_xcvr->set_tx_gain(gain);
}

bool
db_xcvr2450_tx::i_and_q_swapped()
{
  return true;
}


/******************************************************************************/


db_xcvr2450_rx::db_xcvr2450_rx(usrp_basic_sptr usrp, int which)
  : db_xcvr2450_base(usrp, which)
{
  /*
   * @param usrp: instance of usrp.source_c
   * @param which: 0 or 1 corresponding to side RX_A or RX_B respectively.
   */
  set_lo_offset(LO_OFFSET);
  //printf("db_xcvr2450_rx:d_xcvr_2450_rx\n");
}

db_xcvr2450_rx::~db_xcvr2450_rx()
{
  shutdown();
}

void
db_xcvr2450_rx::shutdown()
{
  if (!d_is_shutdown){
    d_is_shutdown = true;
    shutdown_common();
  }
}

float
db_xcvr2450_rx::gain_min()
{
  return 0.0;
}

float
db_xcvr2450_rx::gain_max()
{
  return 92.0;
}

float
db_xcvr2450_rx::gain_db_per_step()
{
  return 1;
}

bool
db_xcvr2450_rx::set_gain(float gain)
{
  return d_xcvr->set_rx_gain(gain);
}