path: root/usrp2/firmware/lib/db_bitshark_rx.c

/*
 * Copyright 2010 Free Software Foundation, Inc.
 *
 * 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/>.
 *
 */

#include "db_bitshark_rx.h"
#include <memory_map.h>
#include <db_base.h>
#include <hal_io.h>
#include <mdelay.h>
#include <lsdac.h>
#include <clocks.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <i2c.h>

/* Note: Thie general structure of this file is based on the db_wbxng.c 
   codebase for the wbx daughterboard. */

/* The following defines specify the address map provided by the
   Bitshark USRP Rx (BURX) board. These registers are all accessed over I2C. */
#define RF_CENTER_FREQ_REG 0x00
#define RF_CHAN_FILTER_BW_REG 0x01
#define RF_GAIN_REG 0x02
#define BB_GAIN_REG 0x03
#define ADF4350_REG 0x10
#define SKY73202_REG 0x11
#define CLOCK_SCHEME_REG 0x20

/* The following table lists the registers provided by the Bitshark board 
   that are accessible over I2C:
   --------------------------------------------------------
   |RegAddr: 0x00-RF Center Freq register |
       |4-bytes 0x00|
       |4-byte unsigned RF center freq (in KHz)|
   |RegAddr: 0x01-RF channel filter bandwidth register |
       |4-bytes 0x00|
       |4-byte unsigned RF channel filter bw (in KHz)|
   |RegAddr: 0x02-RF gain register |
       |7-bytes 0x00|
       |1-byte signed RF gain (in dB)|
   |RegAddr: 0x03-Baseband gain register |
       |4-bytes 0x00|
       |4-byte signed baseband filter gain (in dB)|
   |RegAddr: 0x10-ADF4350 register |
       |4-bytes 0x00|
       |4-byte ADF4350 register value (actual ADF4350 reg addr embedded 
        within 4-byte value)|
   |RegAddr: 0x11-SKY73202 register |
       |5-bytes 0x00|
       |1-byte reg 0 of SKY73202 |
       |1-byte reg 1 of SKY73202 |
       |1-byte reg 2 of SKY73202 |
   |RegAddr: 0x20-Clock Scheme |
       |3-bytes 0x00|
       |1-byte indicating clocking scheme:
        -0x00 -> BURX local TCXO off, BURX accepts ref clock from
	         USRP2 (freq of USRP2's ref clock specified in bytes 2-5)
	-0x01 -> BURX local TCXO on, BURX uses its local TCXO as its ref
	         clock, TCXO signal output for use as phase lock for USRP2 |
       |4-byte USRP2 ref clock freq in hz (only needed if byte 1 set to 0x00) |
       
  ---------------------------------------------------------------------------
   
   As an example, lets say the client wants to set an RF center freq of
   1000 MHz.  In KHz, this translates to 1000000 (resolution is only down to
   steps of 1 KHz), which is 0x000F4240 in hex.  So the complete 9-byte I2C 
   sequence that the client should send is as follows:
   byte 0: 0x00-register 0x00 is the target of the write operation
   bytes 1-4: 0x00 (padding)
   byte 5: 0x00 (MSB of the 1000000 KHz value, in hex)
   byte 6: 0x0F
   byte 7: 0x42
   byte 8: 0x40 (LSB of the 1000000 KHz value, in hex)
   
   How about another example...lets say the client wants to setup the clock
   scheme to use scheme #1 where the 26 MHz TCXO on the BURX board is enabled,
   and is provided to the USRP2 for it to phase lock to it as an external ref.  
   26 MHz (i.e. 26 million), in hex, is 0x18CBA80.
   So the complete 9-byte I2C sequence that the client should send is as follows:
   byte 0: 0x20-register 0x20 is the target of the write operation
   bytes 1-3: 0x00 (padding)
   byte 4: 0x01 (indicating that clock scheme #1 is wanted)
   byte 5: 0x01 (MSB of the BURX ref clk freq)
   byte 6: 0x8C
   byte 7: 0xBA
   byte 8: 0x80 (LSB of the BURX ref clk freq)

   Note: The endian-ness of 4-byte values used in I2C cmds is different on 
   USRP2 compared to USRP1.
   
*/

#define NUM_BYTES_IN_I2C_CMD 9
#define I2C_ADDR 0x47

bool bitshark_rx_init(struct db_base *dbb);
bool bitshark_rx_set_freq(struct db_base *dbb, u2_fxpt_freq_t freq, u2_fxpt_freq_t *dc);
bool bitshark_rx_set_gain(struct db_base *dbb, u2_fxpt_gain_t gain);
bool bitshark_rx_set_bw(struct db_base *dbb, uint16_t bw);

static bool set_clock_scheme(uint8_t clock_scheme, uint32_t ref_clk_freq);

/*
 * The class instances
 */
struct db_bitshark_rx db_bitshark_rx = {
    .base.dbid = 0x0070,
    .base.is_tx = false,
    .base.output_enables = 0x0000,
    .base.used_pins = 0x0000,
    .base.freq_min = U2_DOUBLE_TO_FXPT_FREQ(300e6),
    .base.freq_max = U2_DOUBLE_TO_FXPT_FREQ(4000e6),
    .base.gain_min = U2_DOUBLE_TO_FXPT_GAIN(0),
    .base.gain_max = U2_DOUBLE_TO_FXPT_GAIN(42),
    .base.gain_step_size = U2_DOUBLE_TO_FXPT_GAIN(6),
    .base.is_quadrature = true,
    .base.i_and_q_swapped = true,
    .base.spectrum_inverted = false,
    .base.default_lo_offset = U2_DOUBLE_TO_FXPT_FREQ(0),
    .base.init = bitshark_rx_init,
    .base.set_freq = bitshark_rx_set_freq,
    .base.set_gain = bitshark_rx_set_gain,
    .base.set_tx_enable = 0,
    .base.atr_mask = 0x0000,
    .base.atr_txval = 0,
    .base.atr_rxval = 0,
    .base.set_antenna = 0,
    .extra.bw_min = 660, /* in KHz, so 660 KHz */
    .extra.bw_max = 56000, /* in KHz, so 56 MHz */
    .extra.set_bw = bitshark_rx_set_bw
};

bool
bitshark_rx_init(struct db_base *dbb)
{
    struct db_bitshark_rx_dummy *db = (struct db_bitshark_rx_dummy *) dbb;    

    clocks_enable_rx_dboard(true, 0);
    /* hal_gpio_write( GPIO_RX_BANK, ENABLE_5|ENABLE_33, ENABLE_5|ENABLE_33 ); */
    /* above isn't needed, since we don't have any GPIO from the FPGA */
    
    /* setup the clock scheme to accept the USRP2's 100 MHz ref clk */
    set_clock_scheme(0,100000000);

    /* initial setting of gain */
    dbb->set_gain(dbb,U2_DOUBLE_TO_FXPT_GAIN(20.0));
    
    /* Set the freq now to get the one time 10ms delay out of the way. */
    u2_fxpt_freq_t	dc;
    dbb->set_freq(dbb, dbb->freq_min, &dc);

    /* set up the RF bandwidth of the signal of interest...Note: there
       doesn't appear to be a standard way of setting this bandwidth
       in USRP2-land (compared to USRP1-land, where we have the
       straight-forward set_bw() method).  Not sure why this is, but
       for now, simply set the bandwidth once for the intended
       application. */
    db->extra.set_bw(dbb, 20000);  /* 20 MHz channel bw */
    
    return true;
}

bool
bitshark_rx_set_freq(struct db_base *dbb, u2_fxpt_freq_t freq, u2_fxpt_freq_t *dc)
{
    struct db_bitshark_rx_dummy *db = (struct db_bitshark_rx_dummy *) dbb;    
    unsigned char args[NUM_BYTES_IN_I2C_CMD];
    unsigned char val[4];
    uint32_t freq_in_khz = (uint32_t)(u2_fxpt_freq_to_double(freq)/1000.0);
    
    if(!(freq>=db->base.freq_min && freq<=db->base.freq_max)) 
    {
	return false;
    }
    
    memset(args,0x00,NUM_BYTES_IN_I2C_CMD);
    memcpy(val,&freq_in_khz,4);
    args[0] = RF_CENTER_FREQ_REG;
    args[5] = val[3];
    args[6] = val[2];
    args[7] = val[1];
    args[8] = val[0];
    
    i2c_write(I2C_ADDR, args, NUM_BYTES_IN_I2C_CMD);
    *dc = freq;
    return true;
}

bool
bitshark_rx_set_gain(struct db_base *dbb, u2_fxpt_gain_t gain)
{
    struct db_bitshark_rx_dummy *db = (struct db_bitshark_rx_dummy *) dbb;
    
    unsigned char args[NUM_BYTES_IN_I2C_CMD];
    uint8_t final_gain = (uint8_t)(u2_fxpt_gain_round_to_int(gain));
    
    if(!(gain >= db->base.gain_min && gain <= db->base.gain_max)) 
    {
	return false;
    }
    
    memset(args,0x00,NUM_BYTES_IN_I2C_CMD);
    args[0] = RF_GAIN_REG;
    args[5] = final_gain;

    i2c_write(I2C_ADDR, args, NUM_BYTES_IN_I2C_CMD);

    return true;
}

bool
bitshark_rx_set_bw(struct db_base *dbb, uint16_t bw_in_khz)
{
    struct db_bitshark_rx_dummy *db = (struct db_bitshark_rx_dummy *) dbb;
    unsigned char val[4];
    unsigned char args[NUM_BYTES_IN_I2C_CMD];
    
    if(!(bw_in_khz >= db->extra.bw_min && bw_in_khz <= db->extra.bw_max)) 
    {
	return false;
    }
    
    memset(args,0x00,NUM_BYTES_IN_I2C_CMD);
    memcpy(val,&bw_in_khz,4);
    args[0] = RF_CENTER_FREQ_REG;
    args[5] = val[3];
    args[6] = val[2];
    args[7] = val[1];
    args[8] = val[0];

    i2c_write(I2C_ADDR, args, NUM_BYTES_IN_I2C_CMD);

    return true;
}

static bool
set_clock_scheme(uint8_t clock_scheme, uint32_t ref_clk_freq)
{
    /* Set the clock scheme for determining how the BURX
       dboard receives its clock.  For the USRP2, there is really only
       one way of doing this, which is to use the 100 MHz ref clk
       on the USRP2 as its reference.  However, it is possible to
       use the BURX's 26 MHz TCXO as the external reference input to
       the USRP, which would provide phase lock between our oscillator
       and the USRP's 100 MHz oscillator.  And since the BURX board
       provides the ability to warp the oscillator, this may be
       useful to some folks.  Otherwise, the BURX board will always
       just take the 100 MHz reference from the USRP2 as its reference.
    */
    
    unsigned char args[NUM_BYTES_IN_I2C_CMD];
    char val[4];

    if (clock_scheme > 1) 
    {
	return false;
    }

    memcpy(val,&ref_clk_freq,4);
    args[0] = CLOCK_SCHEME_REG;
    args[4] = clock_scheme;
    args[5] = val[3];
    args[6] = val[2];
    args[7] = val[1];
    args[8] = val[0];

    i2c_write(I2C_ADDR, args, NUM_BYTES_IN_I2C_CMD);

    return true;
}