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Diffstat (limited to 'usrp/host/lib/db_tv_rx.cc')
| -rw-r--r-- | usrp/host/lib/db_tv_rx.cc | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/usrp/host/lib/db_tv_rx.cc b/usrp/host/lib/db_tv_rx.cc new file mode 100644 index 000000000..494ee7a1a --- /dev/null +++ b/usrp/host/lib/db_tv_rx.cc @@ -0,0 +1,274 @@ +// +// Copyright 2008 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_tv_rx.h> +#include <db_base_impl.h> + +/*****************************************************************************/ + +int +control_byte_1(bool fast_tuning_p, int reference_divisor) +{ + int c = 0x88; + if(fast_tuning_p) { + c |= 0x40; + } + + if(reference_divisor == 512) { + c |= 0x3 << 1; + } + else if(reference_divisor == 640) { + c |= 0x0 << 1; + } + else if(reference_divisor == 1024) { + c |= 0x1 << 1; + } + else { + assert(0); + } + + return c; +} + +int +control_byte_2(double target_freq, bool shutdown_tx_PGA) +{ + int c; + if(target_freq < 158e6) { // VHF low + c = 0xa0; + } + else if(target_freq < 464e6) { // VHF high + c = 0x90; + } + else { // UHF + c = 0x30; + } + + if(shutdown_tx_PGA) { + c |= 0x08; + } + + return c; +} + + +/*****************************************************************************/ + + +db_tv_rx::db_tv_rx(usrp_basic_sptr usrp, int which, + double first_IF, double second_IF) + : db_base(usrp, which) +{ + // 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 + + if(which == 0) { + d_i2c_addr = 0x60; + } + else { + d_i2c_addr = 0x61; + } + + d_first_IF = first_IF; + d_second_IF = second_IF; + d_reference_divisor = 640; + d_fast_tuning = false; + d_inverted = false; // FIXME get rid of this + + set_gain((gain_min() + gain_max()) / 2.0); // initialize gain + + bypass_adc_buffers(false); +} + +db_tv_rx::~db_tv_rx() +{ +} + +// Gain setting +void +db_tv_rx::_set_rfagc(float gain) +{ + float voltage; + + assert(gain <= 60 && gain >= 0); + // FIXME this has a 0.5V step between gain = 60 and gain = 59. + // Why are there two cases instead of a single linear case? + if(gain == 60) { + voltage = 4; + } + else { + voltage = gain/60.0 * 2.25 + 1.25; + } + int dacword = int(4096*voltage/1.22/3.3); // 1.22 = opamp gain + + assert(dacword>=0 && dacword<4096); + usrp()->write_aux_dac(d_which, 1, dacword); +} + +void +db_tv_rx::_set_ifagc(float gain) +{ + float voltage; + + assert(gain <= 35 && gain >= 0); + voltage = gain/35.0 * 2.1 + 1.4; + int dacword = int(4096*voltage/1.22/3.3); // 1.22 = opamp gain + + assert(dacword>=0 && dacword<4096); + usrp()->write_aux_dac(d_which, 0, dacword); +} + +void +db_tv_rx::_set_pga(float pga_gain) +{ + assert(pga_gain >=0 && pga_gain <=20); + if(d_which == 0) { + usrp()->set_pga(0, pga_gain); + } + else { + usrp()->set_pga (2, pga_gain); + } +} + +double +db_tv_rx::freq_min() +{ + return 50e6; +} + +double +db_tv_rx::freq_max() +{ + return 860e6; +} + +struct freq_result_t +db_tv_rx::set_freq(double target_freq) +{ + // Set the frequency. + // + // @param freq: target RF frequency in Hz + // @type freq: double + // + // @returns (ok, actual_baseband_freq) where: + // ok is True or False and indicates success or failure, + // actual_baseband_freq is RF frequency that corresponds to DC in the IF. + + freq_result_t args = {false, 0}; + + double fmin = freq_min(); + double fmax = freq_max(); + if((target_freq < fmin) || (target_freq > fmax)) { + return args; + } + + double target_lo_freq = target_freq + d_first_IF; // High side mixing + double f_ref = 4.0e6 / (double)(d_reference_divisor); // frequency steps + + int divisor = int((target_lo_freq + (f_ref * 4)) / (f_ref * 8)); + double actual_lo_freq = (f_ref * 8 * divisor); + double actual_freq = actual_lo_freq - d_first_IF; + + if((divisor & ~0x7fff) != 0) { // must be 15-bits or less + return args; + } + + // build i2c command string + std::vector<int> buf(4); + buf[0] = (divisor >> 8) & 0xff; // DB1 + buf[1] = divisor & 0xff; // DB2 + buf[2] = control_byte_1(d_fast_tuning, d_reference_divisor); + buf[3] = control_byte_2(actual_freq, true); + + args.ok = usrp()->write_i2c(d_i2c_addr, int_seq_to_str (buf)); + args.baseband_freq = actual_freq - d_second_IF; + return args; +} + +float +db_tv_rx::gain_min() +{ + return 0; +} + +float +db_tv_rx::gain_max() +{ + return 115; +} + +float +db_tv_rx::gain_db_per_step() +{ + return 1; +} + +bool +db_tv_rx::set_gain(float gain) +{ + // Set the gain. + // + // @param gain: gain in decibels + // @returns True/False + + float rfgain, ifgain, pgagain; + + assert(gain>=0 && gain<=115); + if(gain>60) { + rfgain = 60; + gain = gain - 60; + } + else { + rfgain = gain; + gain = 0; + } + + if(gain > 35) { + ifgain = 35; + gain = gain - 35; + } + else { + ifgain = gain; + gain = 0; + } + + pgagain = gain; + _set_rfagc(rfgain); + _set_ifagc(ifgain); + _set_pga(pgagain); + + return true; +} + +bool +db_tv_rx::is_quadrature() +{ + // Return True if this board requires both I & Q analog channels. + return false; +} + +bool +db_tv_rx::spectrum_inverted() +{ + // The 43.75 MHz version is inverted + return d_inverted; +} |