// // Copyright 2014 Ettus Research LLC // #include "ad9361_filter_taps.h" #include "ad9361_gain_tables.h" #include "ad9361_synth_lut.h" #include "ad9361_client.h" #include "ad9361_device.h" #define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include //////////////////////////////////////////////////////////// // the following macros evaluate to a compile time constant // macros By Tom Torfs - donated to the public domain /* turn a numeric literal into a hex constant (avoids problems with leading zeroes) 8-bit constants max value 0x11111111, always fits in unsigned long */ #define HEX__(n) 0x##n##LU /* 8-bit conversion function */ #define B8__(x) ((x&0x0000000FLU)?1:0) \ +((x&0x000000F0LU)?2:0) \ +((x&0x00000F00LU)?4:0) \ +((x&0x0000F000LU)?8:0) \ +((x&0x000F0000LU)?16:0) \ +((x&0x00F00000LU)?32:0) \ +((x&0x0F000000LU)?64:0) \ +((x&0xF0000000LU)?128:0) /* for upto 8-bit binary constants */ #define B8(d) ((unsigned char)B8__(HEX__(d))) //////////////////////////////////////////////////////////// namespace uhd { namespace usrp { /* This is a simple comparison for very large double-precision floating * point numbers. It is used to prevent re-tunes for frequencies that are * the same but not 'exactly' because of data precision issues. */ // TODO: see if we can avoid the need for this function int freq_is_nearly_equal(double a, double b) { return std::max(a,b) - std::min(a,b) < 1; } /*********************************************************************** * Filter functions **********************************************************************/ /* This function takes in the calculated maximum number of FIR taps, and * returns a number of taps that makes AD9361 happy. */ int get_num_taps(int max_num_taps) { int num_taps = 0; int num_taps_list[] = {16, 32, 48, 64, 80, 96, 112, 128}; int i; for(i = 1; i < 8; i++) { if(max_num_taps >= num_taps_list[i]) { continue; } else { num_taps = num_taps_list[i - 1]; break; } } if(num_taps == 0) { num_taps = 128; } return num_taps; } const double ad9361_device_t::AD9361_MAX_GAIN = 89.75; const double ad9361_device_t::AD9361_MAX_CLOCK_RATE = 61.44e6; const double ad9361_device_t::AD9361_RECOMMENDED_MAX_CLOCK_RATE = 56e6; /* Program either the RX or TX FIR filter. * * The process is the same for both filters, but the function must be told * how many taps are in the filter, and given a vector of the taps * themselves. */ void ad9361_device_t::_program_fir_filter(direction_t direction, int num_taps, boost::uint16_t *coeffs) { boost::uint16_t base; /* RX and TX filters use largely identical sets of programming registers. Select the appropriate bank of registers here. */ if (direction == RX) { base = 0x0f0; } else { base = 0x060; } /* Encode number of filter taps for programming register */ boost::uint8_t reg_numtaps = (((num_taps / 16) - 1) & 0x07) << 5; /* Turn on the filter clock. */ _io_iface->poke8(base + 5, reg_numtaps | 0x1a); boost::this_thread::sleep(boost::posix_time::milliseconds(1)); /* Zero the unused taps just in case they have stale data */ int addr; for (addr = num_taps; addr < 128; addr++) { _io_iface->poke8(base + 0, addr); _io_iface->poke8(base + 1, 0x0); _io_iface->poke8(base + 2, 0x0); _io_iface->poke8(base + 5, reg_numtaps | 0x1e); _io_iface->poke8(base + 4, 0x00); _io_iface->poke8(base + 4, 0x00); } /* Iterate through indirect programming of filter coeffs using ADI recomended procedure */ for (addr = 0; addr < num_taps; addr++) { _io_iface->poke8(base + 0, addr); _io_iface->poke8(base + 1, (coeffs[addr]) & 0xff); _io_iface->poke8(base + 2, (coeffs[addr] >> 8) & 0xff); _io_iface->poke8(base + 5, reg_numtaps | 0x1e); _io_iface->poke8(base + 4, 0x00); _io_iface->poke8(base + 4, 0x00); } /* UG-671 states (page 25) (paraphrased and clarified): " After the table has been programmed, write to register BASE+5 with the write bit D2 cleared and D1 high. Then, write to register BASE+5 again with D1 clear, thus ensuring that the write bit resets internally before the clock stops. Wait 4 sample clock periods after setting D2 high while that data writes into the table" */ _io_iface->poke8(base + 5, reg_numtaps | 0x1A); if (direction == RX) { _io_iface->poke8(base + 5, reg_numtaps | 0x18); /* Rx Gain, set to prevent digital overflow/saturation in filters 0:+6dB, 1:0dB, 2:-6dB, 3:-12dB page 35 of UG-671 */ _io_iface->poke8(base + 6, 0x02); /* Also turn on -6dB Rx gain here, to stop filter overfow.*/ } else { /* Tx Gain. bit[0]. set to prevent digital overflow/saturation in filters 0: 0dB, 1:-6dB page 25 of UG-671 */ _io_iface->poke8(base + 5, reg_numtaps | 0x18); } } /* Program the RX FIR Filter. */ void ad9361_device_t::_setup_rx_fir(size_t num_taps, boost::int32_t decimation) { if (not (decimation == 1 or decimation == 2 or decimation == 4)) { throw uhd::runtime_error("[ad9361_device_t] Invalid Rx FIR decimation."); } boost::scoped_array coeffs(new boost::uint16_t[num_taps]); for (size_t i = 0; i < num_taps; i++) { switch (num_taps) { case 128: coeffs[i] = boost::uint16_t((decimation==4) ? fir_128_x4_coeffs[i] : hb127_coeffs[i]); break; case 96: coeffs[i] = boost::uint16_t((decimation==4) ? fir_96_x4_coeffs[i] : hb95_coeffs[i]); break; case 64: coeffs[i] = boost::uint16_t((decimation==4) ? fir_64_x4_coeffs[i] : hb63_coeffs[i]); break; case 48: coeffs[i] = boost::uint16_t((decimation==4) ? fir_48_x4_coeffs[i] : hb47_coeffs[i]); break; default: throw uhd::runtime_error("[ad9361_device_t] Unsupported number of Rx FIR taps."); } } _program_fir_filter(RX, num_taps, coeffs.get()); } /* Program the TX FIR Filter. */ void ad9361_device_t::_setup_tx_fir(size_t num_taps, boost::int32_t interpolation) { if (not (interpolation == 1 or interpolation == 2 or interpolation == 4)) { throw uhd::runtime_error("[ad9361_device_t] Invalid Tx FIR interpolation."); } if (interpolation == 1 and num_taps > 64) { throw uhd::runtime_error("[ad9361_device_t] Too many Tx FIR taps for interpolation value."); } boost::scoped_array coeffs(new boost::uint16_t[num_taps]); for (size_t i = 0; i < num_taps; i++) { switch (num_taps) { case 128: coeffs[i] = boost::uint16_t((interpolation==4) ? fir_128_x4_coeffs[i] : hb127_coeffs[i]); break; case 96: coeffs[i] = boost::uint16_t((interpolation==4) ? fir_96_x4_coeffs[i] : hb95_coeffs[i]); break; case 64: coeffs[i] = boost::uint16_t((interpolation==4) ? fir_64_x4_coeffs[i] : hb63_coeffs[i]); break; case 48: coeffs[i] = boost::uint16_t((interpolation==4) ? fir_48_x4_coeffs[i] : hb47_coeffs[i]); break; default: throw uhd::runtime_error("[ad9361_device_t] Unsupported number of Tx FIR taps."); } } _program_fir_filter(TX, num_taps, coeffs.get()); } /*********************************************************************** * Calibration functions ***********************************************************************/ /* Calibrate and lock the BBPLL. * * This function should be called anytime the BBPLL is tuned. */ void ad9361_device_t::_calibrate_lock_bbpll() { _io_iface->poke8(0x03F, 0x05); // Start the BBPLL calibration _io_iface->poke8(0x03F, 0x01); // Clear the 'start' bit /* Increase BBPLL KV and phase margin. */ _io_iface->poke8(0x04c, 0x86); _io_iface->poke8(0x04d, 0x01); _io_iface->poke8(0x04d, 0x05); /* Wait for BBPLL lock. */ size_t count = 0; while (!(_io_iface->peek8(0x05e) & 0x80)) { if (count > 1000) { throw uhd::runtime_error("[ad9361_device_t] BBPLL not locked"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(2)); } } /* Calibrate the synthesizer charge pumps. * * Technically, this calibration only needs to be done once, at device * initialization. */ void ad9361_device_t::_calibrate_synth_charge_pumps() { /* If this function ever gets called, and the ENSM isn't already in the * ALERT state, then something has gone horribly wrong. */ if ((_io_iface->peek8(0x017) & 0x0F) != 5) { throw uhd::runtime_error("[ad9361_device_t] AD9361 not in ALERT during cal"); } /* Calibrate the RX synthesizer charge pump. */ size_t count = 0; _io_iface->poke8(0x23d, 0x04); while (!(_io_iface->peek8(0x244) & 0x80)) { if (count > 5) { throw uhd::runtime_error("[ad9361_device_t] RX charge pump cal failure"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(1)); } _io_iface->poke8(0x23d, 0x00); /* Calibrate the TX synthesizer charge pump. */ count = 0; _io_iface->poke8(0x27d, 0x04); while (!(_io_iface->peek8(0x284) & 0x80)) { if (count > 5) { throw uhd::runtime_error("[ad9361_device_t] TX charge pump cal failure"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(1)); } _io_iface->poke8(0x27d, 0x00); } /* Calibrate the analog BB RX filter. * * Note that the filter calibration depends heavily on the baseband * bandwidth, so this must be re-done after any change to the RX sample * rate. */ double ad9361_device_t::_calibrate_baseband_rx_analog_filter() { /* For filter tuning, baseband BW is half the complex BW, and must be * between 28e6 and 0.2e6. */ double bbbw = _baseband_bw / 2.0; if (bbbw > 28e6) { bbbw = 28e6; } else if (bbbw < 0.20e6) { bbbw = 0.20e6; } double rxtune_clk = ((1.4 * bbbw * 2 * M_PI) / M_LN2); _rx_bbf_tunediv = std::min(511, boost::uint16_t(std::ceil(_bbpll_freq / rxtune_clk))); _regs.bbftune_config = (_regs.bbftune_config & 0xFE) | ((_rx_bbf_tunediv >> 8) & 0x0001); double bbbw_mhz = bbbw / 1e6; double temp = ((bbbw_mhz - std::floor(bbbw_mhz)) * 1000) / 7.8125; boost::uint8_t bbbw_khz = std::min(127, boost::uint8_t(std::floor(temp + 0.5))); /* Set corner frequencies and dividers. */ _io_iface->poke8(0x1fb, (boost::uint8_t) (bbbw_mhz)); _io_iface->poke8(0x1fc, bbbw_khz); _io_iface->poke8(0x1f8, (_rx_bbf_tunediv & 0x00FF)); _io_iface->poke8(0x1f9, _regs.bbftune_config); /* RX Mix Voltage settings - only change with apps engineer help. */ _io_iface->poke8(0x1d5, 0x3f); _io_iface->poke8(0x1c0, 0x03); /* Enable RX1 & RX2 filter tuners. */ _io_iface->poke8(0x1e2, 0x02); _io_iface->poke8(0x1e3, 0x02); /* Run the calibration! */ size_t count = 0; _io_iface->poke8(0x016, 0x80); while (_io_iface->peek8(0x016) & 0x80) { if (count > 100) { throw uhd::runtime_error("[ad9361_device_t] RX baseband filter cal FAILURE"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(1)); } /* Disable RX1 & RX2 filter tuners. */ _io_iface->poke8(0x1e2, 0x03); _io_iface->poke8(0x1e3, 0x03); return bbbw; } /* Calibrate the analog BB TX filter. * * Note that the filter calibration depends heavily on the baseband * bandwidth, so this must be re-done after any change to the TX sample * rate. */ double ad9361_device_t::_calibrate_baseband_tx_analog_filter() { /* For filter tuning, baseband BW is half the complex BW, and must be * between 28e6 and 0.2e6. */ double bbbw = _baseband_bw / 2.0; if (bbbw > 20e6) { bbbw = 20e6; } else if (bbbw < 0.625e6) { bbbw = 0.625e6; } double txtune_clk = ((1.6 * bbbw * 2 * M_PI) / M_LN2); boost::uint16_t txbbfdiv = std::min(511, boost::uint16_t(std::ceil(_bbpll_freq / txtune_clk))); _regs.bbftune_mode = (_regs.bbftune_mode & 0xFE) | ((txbbfdiv >> 8) & 0x0001); /* Program the divider values. */ _io_iface->poke8(0x0d6, (txbbfdiv & 0x00FF)); _io_iface->poke8(0x0d7, _regs.bbftune_mode); /* Enable the filter tuner. */ _io_iface->poke8(0x0ca, 0x22); /* Calibrate! */ size_t count = 0; _io_iface->poke8(0x016, 0x40); while (_io_iface->peek8(0x016) & 0x40) { if (count > 100) { throw uhd::runtime_error("[ad9361_device_t] TX baseband filter cal FAILURE"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(1)); } /* Disable the filter tuner. */ _io_iface->poke8(0x0ca, 0x26); return bbbw; } /* Calibrate the secondary TX filter. * * This filter also depends on the TX sample rate, so if a rate change is * made, the previous calibration will no longer be valid. */ void ad9361_device_t::_calibrate_secondary_tx_filter() { /* For filter tuning, baseband BW is half the complex BW, and must be * between 20e6 and 0.53e6. */ double bbbw = _baseband_bw / 2.0; if (bbbw > 20e6) { bbbw = 20e6; } else if (bbbw < 0.53e6) { bbbw = 0.53e6; } double bbbw_mhz = bbbw / 1e6; /* Start with a resistor value of 100 Ohms. */ int res = 100; /* Calculate target corner frequency. */ double corner_freq = 5 * bbbw_mhz * 2 * M_PI; /* Iterate through RC values to determine correct combination. */ int cap = 0; int i; for (i = 0; i <= 3; i++) { cap = static_cast(std::floor(0.5 + ((1 / ((corner_freq * res) * 1e6)) * 1e12))) - 12; if (cap <= 63) { break; } res = res * 2; } if (cap > 63) { cap = 63; } boost::uint8_t reg0d0, reg0d1, reg0d2; /* Translate baseband bandwidths to register settings. */ if ((bbbw_mhz * 2) <= 9) { reg0d0 = 0x59; } else if (((bbbw_mhz * 2) > 9) && ((bbbw_mhz * 2) <= 24)) { reg0d0 = 0x56; } else if ((bbbw_mhz * 2) > 24) { reg0d0 = 0x57; } else { throw uhd::runtime_error("[ad9361_device_t] Cal2ndTxFil: INVALID_CODE_PATH bad bbbw_mhz"); reg0d0 = 0x00; } /* Translate resistor values to register settings. */ if (res == 100) { reg0d1 = 0x0c; } else if (res == 200) { reg0d1 = 0x04; } else if (res == 400) { reg0d1 = 0x03; } else if (res == 800) { reg0d1 = 0x01; } else { reg0d1 = 0x0c; } reg0d2 = cap; /* Program the above-calculated values. Sweet. */ _io_iface->poke8(0x0d2, reg0d2); _io_iface->poke8(0x0d1, reg0d1); _io_iface->poke8(0x0d0, reg0d0); } /* Calibrate the RX TIAs. * * Note that the values in the TIA register, after calibration, vary with * the RX gain settings. */ void ad9361_device_t::_calibrate_rx_TIAs() { boost::uint8_t reg1eb = _io_iface->peek8(0x1eb) & 0x3F; boost::uint8_t reg1ec = _io_iface->peek8(0x1ec) & 0x7F; boost::uint8_t reg1e6 = _io_iface->peek8(0x1e6) & 0x07; boost::uint8_t reg1db = 0x00; boost::uint8_t reg1dc = 0x00; boost::uint8_t reg1dd = 0x00; boost::uint8_t reg1de = 0x00; boost::uint8_t reg1df = 0x00; /* For calibration, baseband BW is half the complex BW, and must be * between 28e6 and 0.2e6. */ double bbbw = _baseband_bw / 2.0; if (bbbw > 20e6) { bbbw = 20e6; } else if (bbbw < 0.20e6) { bbbw = 0.20e6; } double ceil_bbbw_mhz = std::ceil(bbbw / 1e6); /* Do some crazy resistor and capacitor math. */ int Cbbf = (reg1eb * 160) + (reg1ec * 10) + 140; int R2346 = 18300 * (reg1e6 & 0x07); double CTIA_fF = (Cbbf * R2346 * 0.56) / 3500; /* Translate baseband BW to register settings. */ if (ceil_bbbw_mhz <= 3) { reg1db = 0xe0; } else if ((ceil_bbbw_mhz > 3) && (ceil_bbbw_mhz <= 10)) { reg1db = 0x60; } else if (ceil_bbbw_mhz > 10) { reg1db = 0x20; } else { throw uhd::runtime_error("[ad9361_device_t] CalRxTias: INVALID_CODE_PATH bad bbbw_mhz"); } if (CTIA_fF > 2920) { reg1dc = 0x40; reg1de = 0x40; boost::uint8_t temp = (boost::uint8_t) std::min(127, boost::uint8_t(std::floor(0.5 + ((CTIA_fF - 400.0) / 320.0)))); reg1dd = temp; reg1df = temp; } else { boost::uint8_t temp = boost::uint8_t(std::floor(0.5 + ((CTIA_fF - 400.0) / 40.0)) + 0x40); reg1dc = temp; reg1de = temp; reg1dd = 0; reg1df = 0; } /* w00t. Settings calculated. Program them and roll out. */ _io_iface->poke8(0x1db, reg1db); _io_iface->poke8(0x1dd, reg1dd); _io_iface->poke8(0x1df, reg1df); _io_iface->poke8(0x1dc, reg1dc); _io_iface->poke8(0x1de, reg1de); } /* Setup the AD9361 ADC. * * There are 40 registers that control the ADC's operation, most of the * values of which must be derived mathematically, dependent on the current * setting of the BBPLL. Note that the order of calculation is critical, as * some of the 40 registers depend on the values in others. */ void ad9361_device_t::_setup_adc() { double bbbw_mhz = (((_bbpll_freq / 1e6) / _rx_bbf_tunediv) * M_LN2) \ / (1.4 * 2 * M_PI); /* For calibration, baseband BW is half the complex BW, and must be * between 28e6 and 0.2e6. */ if(bbbw_mhz > 28) { bbbw_mhz = 28; } else if (bbbw_mhz < 0.20) { bbbw_mhz = 0.20; } boost::uint8_t rxbbf_c3_msb = _io_iface->peek8(0x1eb) & 0x3F; boost::uint8_t rxbbf_c3_lsb = _io_iface->peek8(0x1ec) & 0x7F; boost::uint8_t rxbbf_r2346 = _io_iface->peek8(0x1e6) & 0x07; double fsadc = _adcclock_freq / 1e6; /* Sort out the RC time constant for our baseband bandwidth... */ double rc_timeconst = 0.0; if(bbbw_mhz < 18) { rc_timeconst = (1 / ((1.4 * 2 * M_PI) \ * (18300 * rxbbf_r2346) * ((160e-15 * rxbbf_c3_msb) + (10e-15 * rxbbf_c3_lsb) + 140e-15) * (bbbw_mhz * 1e6))); } else { rc_timeconst = (1 / ((1.4 * 2 * M_PI) \ * (18300 * rxbbf_r2346) * ((160e-15 * rxbbf_c3_msb) + (10e-15 * rxbbf_c3_lsb) + 140e-15) * (bbbw_mhz * 1e6) * (1 + (0.01 * (bbbw_mhz - 18))))); } double scale_res = sqrt(1 / rc_timeconst); double scale_cap = sqrt(1 / rc_timeconst); double scale_snr = (_adcclock_freq < 80e6) ? 1.0 : 1.584893192; double maxsnr = 640 / 160; /* Calculate the values for all 40 settings registers. * * DO NOT TOUCH THIS UNLESS YOU KNOW EXACTLY WHAT YOU ARE DOING. kthx.*/ boost::uint8_t data[40]; data[0] = 0; data[1] = 0; data[2] = 0; data[3] = 0x24; data[4] = 0x24; data[5] = 0; data[6] = 0; data[7] = std::min(124, boost::uint8_t(std::floor(-0.5 + (80.0 * scale_snr * scale_res * std::min(1.0, sqrt(maxsnr * fsadc / 640.0)))))); double data007 = data[7]; data[8] = std::min(255, boost::uint8_t(std::floor(0.5 + ((20.0 * (640.0 / fsadc) * ((data007 / 80.0)) / (scale_res * scale_cap)))))); data[10] = std::min(127, boost::uint8_t(std::floor(-0.5 + (77.0 * scale_res * std::min(1.0, sqrt(maxsnr * fsadc / 640.0)))))); double data010 = data[10]; data[9] = std::min(127, boost::uint8_t(std::floor(0.8 * data010))); data[11] = std::min(255, boost::uint8_t(std::floor(0.5 + (20.0 * (640.0 / fsadc) * ((data010 / 77.0) / (scale_res * scale_cap)))))); data[12] = std::min(127, boost::uint8_t(std::floor(-0.5 + (80.0 * scale_res * std::min(1.0, sqrt(maxsnr * fsadc / 640.0)))))); double data012 = data[12]; data[13] = std::min(255, boost::uint8_t(std::floor(-1.5 + (20.0 * (640.0 / fsadc) * ((data012 / 80.0) / (scale_res * scale_cap)))))); data[14] = 21 * boost::uint8_t(std::floor(0.1 * 640.0 / fsadc)); data[15] = std::min(127, boost::uint8_t(1.025 * data007)); double data015 = data[15]; data[16] = std::min(127, boost::uint8_t(std::floor((data015 * (0.98 + (0.02 * std::max(1.0, (640.0 / fsadc) / maxsnr))))))); data[17] = data[15]; data[18] = std::min(127, boost::uint8_t(0.975 * (data010))); double data018 = data[18]; data[19] = std::min(127, boost::uint8_t(std::floor((data018 * (0.98 + (0.02 * std::max(1.0, (640.0 / fsadc) / maxsnr))))))); data[20] = data[18]; data[21] = std::min(127, boost::uint8_t(0.975 * data012)); double data021 = data[21]; data[22] = std::min(127, boost::uint8_t(std::floor((data021 * (0.98 + (0.02 * std::max(1.0, (640.0 / fsadc) / maxsnr))))))); data[23] = data[21]; data[24] = 0x2e; data[25] = boost::uint8_t(std::floor(128.0 + std::min(63.0, 63.0 * (fsadc / 640.0)))); data[26] = boost::uint8_t(std::floor(std::min(63.0, 63.0 * (fsadc / 640.0) * (0.92 + (0.08 * (640.0 / fsadc)))))); data[27] = boost::uint8_t(std::floor(std::min(63.0, 32.0 * sqrt(fsadc / 640.0)))); data[28] = boost::uint8_t(std::floor(128.0 + std::min(63.0, 63.0 * (fsadc / 640.0)))); data[29] = boost::uint8_t(std::floor(std::min(63.0, 63.0 * (fsadc / 640.0) * (0.92 + (0.08 * (640.0 / fsadc)))))); data[30] = boost::uint8_t(std::floor(std::min(63.0, 32.0 * sqrt(fsadc / 640.0)))); data[31] = boost::uint8_t(std::floor(128.0 + std::min(63.0, 63.0 * (fsadc / 640.0)))); data[32] = boost::uint8_t(std::floor(std::min(63.0, 63.0 * (fsadc / 640.0) * (0.92 + (0.08 * (640.0 / fsadc)))))); data[33] = boost::uint8_t(std::floor(std::min(63.0, 63.0 * sqrt(fsadc / 640.0)))); data[34] = std::min(127, boost::uint8_t(std::floor(64.0 * sqrt(fsadc / 640.0)))); data[35] = 0x40; data[36] = 0x40; data[37] = 0x2c; data[38] = 0x00; data[39] = 0x00; /* Program the registers! */ for(size_t i = 0; i < 40; i++) { _io_iface->poke8(0x200+i, data[i]); } } /* Calibrate the baseband DC offset. * * Note that this function is called from within the TX quadrature * calibration function! */ void ad9361_device_t::_calibrate_baseband_dc_offset() { _io_iface->poke8(0x193, 0x3f); // Calibration settings _io_iface->poke8(0x190, 0x0f); // Set tracking coefficient //write_ad9361_reg(device, 0x190, /*0x0f*//*0xDF*/0x80*1 | 0x40*1 | (16+8/*+4*/)); // Set tracking coefficient: don't *4 counter, do decim /4, increased gain shift _io_iface->poke8(0x194, 0x01); // More calibration settings /* Start that calibration, baby. */ size_t count = 0; _io_iface->poke8(0x016, 0x01); while (_io_iface->peek8(0x016) & 0x01) { if (count > 100) { throw uhd::runtime_error("[ad9361_device_t] Baseband DC Offset Calibration Failure"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(5)); } } /* Calibrate the RF DC offset. * * Note that this function is called from within the TX quadrature * calibration function. */ void ad9361_device_t::_calibrate_rf_dc_offset() { /* Some settings are frequency-dependent. */ if (_rx_freq < 4e9) { _io_iface->poke8(0x186, 0x32); // RF DC Offset count _io_iface->poke8(0x187, 0x24); _io_iface->poke8(0x188, 0x05); } else { _io_iface->poke8(0x186, 0x28); // RF DC Offset count _io_iface->poke8(0x187, 0x34); _io_iface->poke8(0x188, 0x06); } _io_iface->poke8(0x185, 0x20); // RF DC Offset wait count _io_iface->poke8(0x18b, 0x83); _io_iface->poke8(0x189, 0x30); /* Run the calibration! */ size_t count = 0; _io_iface->poke8(0x016, 0x02); while (_io_iface->peek8(0x016) & 0x02) { if (count > 100) { throw uhd::runtime_error("[ad9361_device_t] RF DC Offset Calibration Failure"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(50)); } } /* Start the RX quadrature calibration. * * Note that we are using AD9361's 'tracking' feature for RX quadrature * calibration, so once it starts it continues to free-run during operation. * It should be re-run for large frequency changes. */ void ad9361_device_t::_calibrate_rx_quadrature() { /* Configure RX Quadrature calibration settings. */ _io_iface->poke8(0x168, 0x03); // Set tone level for cal _io_iface->poke8(0x16e, 0x25); // RX Gain index to use for cal _io_iface->poke8(0x16a, 0x75); // Set Kexp phase _io_iface->poke8(0x16b, 0x15); // Set Kexp amplitude _io_iface->poke8(0x169, 0xcf); // Continuous tracking mode _io_iface->poke8(0x18b, 0xad); } /* TX quadtrature calibration routine. * * The TX quadrature needs to be done twice, once for each TX chain, with * only one register change in between. Thus, this function enacts the * calibrations, and it is called from calibrate_tx_quadrature. */ void ad9361_device_t::_tx_quadrature_cal_routine() { /* This is a weird process, but here is how it works: * 1) Read the calibrated NCO frequency bits out of 0A3. * 2) Write the two bits to the RX NCO freq part of 0A0. * 3) Re-read 0A3 to get bits [5:0] because maybe they changed? * 4) Update only the TX NCO freq bits in 0A3. * 5) Profit (I hope). */ boost::uint8_t reg0a3 = _io_iface->peek8(0x0a3); boost::uint8_t nco_freq = (reg0a3 & 0xC0); _io_iface->poke8(0x0a0, 0x15 | (nco_freq >> 1)); reg0a3 = _io_iface->peek8(0x0a3); _io_iface->poke8(0x0a3, (reg0a3 & 0x3F) | nco_freq); /* It is possible to reach a configuration that won't operate correctly, * where the two test tones used for quadrature calibration are outside * of the RX BBF, and therefore don't make it to the ADC. We will check * for that scenario here. */ double max_cal_freq = (((_baseband_bw * _tfir_factor) * ((nco_freq >> 6) + 1)) / 32) * 2; double bbbw = _baseband_bw / 2.0; // bbbw represents the one-sided BW if (bbbw > 28e6) { bbbw = 28e6; } else if (bbbw < 0.20e6) { bbbw = 0.20e6; } if (max_cal_freq > bbbw) throw uhd::runtime_error("[ad9361_device_t] max_cal_freq > bbbw"); _io_iface->poke8(0x0a1, 0x7B); // Set tracking coefficient _io_iface->poke8(0x0a9, 0xff); // Cal count _io_iface->poke8(0x0a2, 0x7f); // Cal Kexp _io_iface->poke8(0x0a5, 0x01); // Cal magnitude threshold VVVV _io_iface->poke8(0x0a6, 0x01); /* The gain table index used for calibration must be adjusted for the * mid-table to get a TIA index = 1 and LPF index = 0. */ if ((_rx_freq >= 1300e6) && (_rx_freq < 4000e6)) { _io_iface->poke8(0x0aa, 0x22); // Cal gain table index } else { _io_iface->poke8(0x0aa, 0x25); // Cal gain table index } _io_iface->poke8(0x0a4, 0xf0); // Cal setting conut _io_iface->poke8(0x0ae, 0x00); // Cal LPF gain index (split mode) /* First, calibrate the baseband DC offset. */ _calibrate_baseband_dc_offset(); /* Second, calibrate the RF DC offset. */ _calibrate_rf_dc_offset(); /* Now, calibrate the TX quadrature! */ size_t count = 0; _io_iface->poke8(0x016, 0x10); while (_io_iface->peek8(0x016) & 0x10) { if (count > 100) { throw uhd::runtime_error("[ad9361_device_t] TX Quadrature Calibration Failure"); break; } count++; boost::this_thread::sleep(boost::posix_time::milliseconds(10)); } } /* Run the TX quadrature calibration. * * Note that from within this function we are also triggering the baseband * and RF DC calibrations. */ void ad9361_device_t::_calibrate_tx_quadrature() { /* Make sure we are, in fact, in the ALERT state. If not, something is * terribly wrong in the driver execution flow. */ if ((_io_iface->peek8(0x017) & 0x0F) != 5) { throw uhd::runtime_error("[ad9361_device_t] TX Quad Cal started, but not in ALERT"); } /* Turn off free-running and continuous calibrations. Note that this * will get turned back on at the end of the RX calibration routine. */ _io_iface->poke8(0x169, 0xc0); /* This calibration must be done in a certain order, and for both TX_A * and TX_B, separately. Store the original setting so that we can * restore it later. */ boost::uint8_t orig_reg_inputsel = _regs.inputsel; /*********************************************************************** * TX1/2-A Calibration **********************************************************************/ _regs.inputsel = _regs.inputsel & 0xBF; _io_iface->poke8(0x004, _regs.inputsel); _tx_quadrature_cal_routine(); /*********************************************************************** * TX1/2-B Calibration **********************************************************************/ _regs.inputsel = _regs.inputsel | 0x40; _io_iface->poke8(0x004, _regs.inputsel); _tx_quadrature_cal_routine(); /*********************************************************************** * fin **********************************************************************/ _regs.inputsel = orig_reg_inputsel; _io_iface->poke8(0x004, orig_reg_inputsel); } /*********************************************************************** * Other Misc Setup Functions ***********************************************************************/ /* Program the mixer gain table. * * Note that this table is fixed for all frequency settings. */ void ad9361_device_t::_program_mixer_gm_subtable() { boost::uint8_t gain[] = { 0x78, 0x74, 0x70, 0x6C, 0x68, 0x64, 0x60, 0x5C, 0x58, 0x54, 0x50, 0x4C, 0x48, 0x30, 0x18, 0x00 }; boost::uint8_t gm[] = { 0x00, 0x0D, 0x15, 0x1B, 0x21, 0x25, 0x29, 0x2C, 0x2F, 0x31, 0x33, 0x34, 0x35, 0x3A, 0x3D, 0x3E }; /* Start the clock. */ _io_iface->poke8(0x13f, 0x02); /* Program the GM Sub-table. */ int i; for (i = 15; i >= 0; i--) { _io_iface->poke8(0x138, i); _io_iface->poke8(0x139, gain[(15 - i)]); _io_iface->poke8(0x13A, 0x00); _io_iface->poke8(0x13B, gm[(15 - i)]); _io_iface->poke8(0x13F, 0x06); _io_iface->poke8(0x13C, 0x00); _io_iface->poke8(0x13C, 0x00); } /* Clear write bit and stop clock. */ _io_iface->poke8(0x13f, 0x02); _io_iface->poke8(0x13C, 0x00); _io_iface->poke8(0x13C, 0x00); _io_iface->poke8(0x13f, 0x00); } /* Program the gain table. * * There are three different gain tables for different frequency ranges! */ void ad9361_device_t::_program_gain_table() { /* Figure out which gain table we should be using for our current * frequency band. */ boost::uint8_t (*gain_table)[5] = NULL; boost::uint8_t new_gain_table; if (_rx_freq < 1300e6) { gain_table = gain_table_sub_1300mhz; new_gain_table = 1; } else if (_rx_freq < 4e9) { gain_table = gain_table_1300mhz_to_4000mhz; new_gain_table = 2; } else if (_rx_freq <= 6e9) { gain_table = gain_table_4000mhz_to_6000mhz; new_gain_table = 3; } else { throw uhd::runtime_error("[ad9361_device_t] Wrong _rx_freq value"); new_gain_table = 1; } /* Only re-program the gain table if there has been a band change. */ if (_curr_gain_table == new_gain_table) { return; } else { _curr_gain_table = new_gain_table; } /* Okay, we have to program a new gain table. Sucks, brah. Start the * gain table clock. */ _io_iface->poke8(0x137, 0x1A); /* IT'S PROGRAMMING TIME. */ boost::uint8_t index = 0; for (; index < 77; index++) { _io_iface->poke8(0x130, index); _io_iface->poke8(0x131, gain_table[index][1]); _io_iface->poke8(0x132, gain_table[index][2]); _io_iface->poke8(0x133, gain_table[index][3]); _io_iface->poke8(0x137, 0x1E); _io_iface->poke8(0x134, 0x00); _io_iface->poke8(0x134, 0x00); } /* Everything above the 77th index is zero. */ for (; index < 91; index++) { _io_iface->poke8(0x130, index); _io_iface->poke8(0x131, 0x00); _io_iface->poke8(0x132, 0x00); _io_iface->poke8(0x133, 0x00); _io_iface->poke8(0x137, 0x1E); _io_iface->poke8(0x134, 0x00); _io_iface->poke8(0x134, 0x00); } /* Clear the write bit and stop the gain clock. */ _io_iface->poke8(0x137, 0x1A); _io_iface->poke8(0x134, 0x00); _io_iface->poke8(0x134, 0x00); _io_iface->poke8(0x137, 0x00); } /* Setup gain control registers. * * This really only needs to be done once, at initialization. */ void ad9361_device_t::_setup_gain_control() { _io_iface->poke8(0x0FA, 0xE0); // Gain Control Mode Select _io_iface->poke8(0x0FB, 0x08); // Table, Digital Gain, Man Gain Ctrl _io_iface->poke8(0x0FC, 0x23); // Incr Step Size, ADC Overrange Size _io_iface->poke8(0x0FD, 0x4C); // Max Full/LMT Gain Table Index _io_iface->poke8(0x0FE, 0x44); // Decr Step Size, Peak Overload Time _io_iface->poke8(0x100, 0x6F); // Max Digital Gain _io_iface->poke8(0x104, 0x2F); // ADC Small Overload Threshold _io_iface->poke8(0x105, 0x3A); // ADC Large Overload Threshold _io_iface->poke8(0x107, 0x31); // Large LMT Overload Threshold _io_iface->poke8(0x108, 0x39); // Small LMT Overload Threshold _io_iface->poke8(0x109, 0x23); // Rx1 Full/LMT Gain Index _io_iface->poke8(0x10A, 0x58); // Rx1 LPF Gain Index _io_iface->poke8(0x10B, 0x00); // Rx1 Digital Gain Index _io_iface->poke8(0x10C, 0x23); // Rx2 Full/LMT Gain Index _io_iface->poke8(0x10D, 0x18); // Rx2 LPF Gain Index _io_iface->poke8(0x10E, 0x00); // Rx2 Digital Gain Index _io_iface->poke8(0x114, 0x30); // Low Power Threshold _io_iface->poke8(0x11A, 0x27); // Initial LMT Gain Limit _io_iface->poke8(0x081, 0x00); // Tx Symbol Gain Control } /* Setup the RX or TX synthesizers. * * This setup depends on a fixed look-up table, which is stored in an * included header file. The table is indexed based on the passed VCO rate. */ void ad9361_device_t::_setup_synth(direction_t direction, double vcorate) { /* The vcorates in the vco_index array represent lower boundaries for * rates. Once we find a match, we use that index to look-up the rest of * the register values in the LUT. */ int vcoindex = 0; for (size_t i = 0; i < 53; i++) { vcoindex = i; if (vcorate > vco_index[i]) { break; } } if (vcoindex > 53) throw uhd::runtime_error("[ad9361_device_t] vcoindex > 53"); /* Parse the values out of the LUT based on our calculated index... */ boost::uint8_t vco_output_level = synth_cal_lut[vcoindex][0]; boost::uint8_t vco_varactor = synth_cal_lut[vcoindex][1]; boost::uint8_t vco_bias_ref = synth_cal_lut[vcoindex][2]; boost::uint8_t vco_bias_tcf = synth_cal_lut[vcoindex][3]; boost::uint8_t vco_cal_offset = synth_cal_lut[vcoindex][4]; boost::uint8_t vco_varactor_ref = synth_cal_lut[vcoindex][5]; boost::uint8_t charge_pump_curr = synth_cal_lut[vcoindex][6]; boost::uint8_t loop_filter_c2 = synth_cal_lut[vcoindex][7]; boost::uint8_t loop_filter_c1 = synth_cal_lut[vcoindex][8]; boost::uint8_t loop_filter_r1 = synth_cal_lut[vcoindex][9]; boost::uint8_t loop_filter_c3 = synth_cal_lut[vcoindex][10]; boost::uint8_t loop_filter_r3 = synth_cal_lut[vcoindex][11]; /* ... annnd program! */ if (direction == RX) { _io_iface->poke8(0x23a, 0x40 | vco_output_level); _io_iface->poke8(0x239, 0xC0 | vco_varactor); _io_iface->poke8(0x242, vco_bias_ref | (vco_bias_tcf << 3)); _io_iface->poke8(0x238, (vco_cal_offset << 3)); _io_iface->poke8(0x245, 0x00); _io_iface->poke8(0x251, vco_varactor_ref); _io_iface->poke8(0x250, 0x70); _io_iface->poke8(0x23b, 0x80 | charge_pump_curr); _io_iface->poke8(0x23e, loop_filter_c1 | (loop_filter_c2 << 4)); _io_iface->poke8(0x23f, loop_filter_c3 | (loop_filter_r1 << 4)); _io_iface->poke8(0x240, loop_filter_r3); } else if (direction == TX) { _io_iface->poke8(0x27a, 0x40 | vco_output_level); _io_iface->poke8(0x279, 0xC0 | vco_varactor); _io_iface->poke8(0x282, vco_bias_ref | (vco_bias_tcf << 3)); _io_iface->poke8(0x278, (vco_cal_offset << 3)); _io_iface->poke8(0x285, 0x00); _io_iface->poke8(0x291, vco_varactor_ref); _io_iface->poke8(0x290, 0x70); _io_iface->poke8(0x27b, 0x80 | charge_pump_curr); _io_iface->poke8(0x27e, loop_filter_c1 | (loop_filter_c2 << 4)); _io_iface->poke8(0x27f, loop_filter_c3 | (loop_filter_r1 << 4)); _io_iface->poke8(0x280, loop_filter_r3); } else { throw uhd::runtime_error("[ad9361_device_t] [_setup_synth] INVALID_CODE_PATH"); } } /* Tune the baseband VCO. * * This clock signal is what gets fed to the ADCs and DACs. This function is * not exported outside of this file, and is invoked based on the rate * fed to the public set_clock_rate function. */ double ad9361_device_t::_tune_bbvco(const double rate) { UHD_LOG << boost::format("[ad9361_device_t::_tune_bbvco] rate=%.10f\n") % rate; /* Let's not re-tune to the same frequency over and over... */ if (freq_is_nearly_equal(rate, _req_coreclk)) { return _adcclock_freq; } _req_coreclk = rate; const double fref = 40e6; const int modulus = 2088960; const double vcomax = 1430e6; const double vcomin = 672e6; double vcorate; int vcodiv; /* Iterate over VCO dividers until appropriate divider is found. */ int i = 1; for (; i <= 6; i++) { vcodiv = 1 << i; vcorate = rate * vcodiv; if (vcorate >= vcomin && vcorate <= vcomax) break; } if (i == 7) throw uhd::runtime_error("[ad9361_device_t] _tune_bbvco: wrong vcorate"); UHD_LOG << boost::format("[ad9361_device_t::_tune_bbvco] vcodiv=%d vcorate=%.10f\n") % vcodiv % vcorate; /* Fo = Fref * (Nint + Nfrac / mod) */ int nint = static_cast(vcorate / fref); UHD_LOG << boost::format("[ad9361_device_t::_tune_bbvco] (nint)=%.10f\n") % (vcorate / fref); int nfrac = static_cast(boost::math::round(((vcorate / fref) - (double) nint) * (double) modulus)); UHD_LOG << boost::format("[ad9361_device_t::_tune_bbvco] (nfrac)=%.10f\n") % (((vcorate / fref) - (double) nint) * (double) modulus); UHD_LOG << boost::format("[ad9361_device_t::_tune_bbvco] nint=%d nfrac=%d\n") % nint % nfrac; double actual_vcorate = fref * ((double) nint + ((double) nfrac / (double) modulus)); /* Scale CP current according to VCO rate */ const double icp_baseline = 150e-6; const double freq_baseline = 1280e6; double icp = icp_baseline * (actual_vcorate / freq_baseline); int icp_reg = static_cast(icp / 25e-6) - 1; _io_iface->poke8(0x045, 0x00); // REFCLK / 1 to BBPLL _io_iface->poke8(0x046, icp_reg & 0x3F); // CP current _io_iface->poke8(0x048, 0xe8); // BBPLL loop filters _io_iface->poke8(0x049, 0x5b); // BBPLL loop filters _io_iface->poke8(0x04a, 0x35); // BBPLL loop filters _io_iface->poke8(0x04b, 0xe0); _io_iface->poke8(0x04e, 0x10); // Max accuracy _io_iface->poke8(0x043, nfrac & 0xFF); // Nfrac[7:0] _io_iface->poke8(0x042, (nfrac >> 8) & 0xFF); // Nfrac[15:8] _io_iface->poke8(0x041, (nfrac >> 16) & 0xFF); // Nfrac[23:16] _io_iface->poke8(0x044, nint); // Nint _calibrate_lock_bbpll(); _regs.bbpll = (_regs.bbpll & 0xF8) | i; _bbpll_freq = actual_vcorate; _adcclock_freq = (actual_vcorate / vcodiv); return _adcclock_freq; } /* This function re-programs all of the gains in the system. * * Because the gain values match to different gain indices based on the * current operating band, this function can be called to update all gain * settings to the appropriate index after a re-tune. */ void ad9361_device_t::_reprogram_gains() { set_gain(RX, CHAIN_1,_rx1_gain); set_gain(RX, CHAIN_2,_rx2_gain); set_gain(TX, CHAIN_1,_tx1_gain); set_gain(TX, CHAIN_2,_tx2_gain); } /* This is the internal tune function, not available for a host call. * * Calculate the VCO settings for the requested frquency, and then either * tune the RX or TX VCO. */ double ad9361_device_t::_tune_helper(direction_t direction, const double value) { /* The RFPLL runs from 6 GHz - 12 GHz */ const double fref = 80e6; const int modulus = 8388593; const double vcomax = 12e9; const double vcomin = 6e9; double vcorate; int vcodiv; /* Iterate over VCO dividers until appropriate divider is found. */ int i; for (i = 0; i <= 6; i++) { vcodiv = 2 << i; vcorate = value * vcodiv; if (vcorate >= vcomin && vcorate <= vcomax) break; } if (i == 7) throw uhd::runtime_error("[ad9361_device_t] RFVCO can't find valid VCO rate!"); int nint = static_cast(vcorate / fref); int nfrac = static_cast(((vcorate / fref) - nint) * modulus); double actual_vcorate = fref * (nint + (double) (nfrac) / modulus); double actual_lo = actual_vcorate / vcodiv; if (direction == RX) { _req_rx_freq = value; /* Set band-specific settings. */ if (value < _client_params->get_band_edge(AD9361_RX_BAND0)) { _regs.inputsel = (_regs.inputsel & 0xC0) | 0x30; } else if ((value >= _client_params->get_band_edge(AD9361_RX_BAND0)) && (value < _client_params->get_band_edge(AD9361_RX_BAND1))) { _regs.inputsel = (_regs.inputsel & 0xC0) | 0x0C; } else if ((value >= _client_params->get_band_edge(AD9361_RX_BAND1)) && (value <= 6e9)) { _regs.inputsel = (_regs.inputsel & 0xC0) | 0x03; } else { throw uhd::runtime_error("[ad9361_device_t] [_tune_helper] INVALID_CODE_PATH"); } _io_iface->poke8(0x004, _regs.inputsel); /* Store vcodiv setting. */ _regs.vcodivs = (_regs.vcodivs & 0xF0) | (i & 0x0F); /* Setup the synthesizer. */ _setup_synth(RX, actual_vcorate); /* Tune!!!! */ _io_iface->poke8(0x233, nfrac & 0xFF); _io_iface->poke8(0x234, (nfrac >> 8) & 0xFF); _io_iface->poke8(0x235, (nfrac >> 16) & 0xFF); _io_iface->poke8(0x232, (nint >> 8) & 0xFF); _io_iface->poke8(0x231, nint & 0xFF); _io_iface->poke8(0x005, _regs.vcodivs); /* Lock the PLL! */ boost::this_thread::sleep(boost::posix_time::milliseconds(2)); if ((_io_iface->peek8(0x247) & 0x02) == 0) { throw uhd::runtime_error("[ad9361_device_t] RX PLL NOT LOCKED"); } _rx_freq = actual_lo; return actual_lo; } else { _req_tx_freq = value; /* Set band-specific settings. */ if (value < _client_params->get_band_edge(AD9361_TX_BAND0)) { _regs.inputsel = _regs.inputsel | 0x40; } else if ((value >= _client_params->get_band_edge(AD9361_TX_BAND0)) && (value <= 6e9)) { _regs.inputsel = _regs.inputsel & 0xBF; } else { throw uhd::runtime_error("[ad9361_device_t] [_tune_helper] INVALID_CODE_PATH"); } _io_iface->poke8(0x004, _regs.inputsel); /* Store vcodiv setting. */ _regs.vcodivs = (_regs.vcodivs & 0x0F) | ((i & 0x0F) << 4); /* Setup the synthesizer. */ _setup_synth(TX, actual_vcorate); /* Tune it, homey. */ _io_iface->poke8(0x273, nfrac & 0xFF); _io_iface->poke8(0x274, (nfrac >> 8) & 0xFF); _io_iface->poke8(0x275, (nfrac >> 16) & 0xFF); _io_iface->poke8(0x272, (nint >> 8) & 0xFF); _io_iface->poke8(0x271, nint & 0xFF); _io_iface->poke8(0x005, _regs.vcodivs); /* Lock the PLL! */ boost::this_thread::sleep(boost::posix_time::milliseconds(2)); if ((_io_iface->peek8(0x287) & 0x02) == 0) { throw uhd::runtime_error("[ad9361_device_t] TX PLL NOT LOCKED"); } _tx_freq = actual_lo; return actual_lo; } } /* Configure the various clock / sample rates in the RX and TX chains. * * Functionally, this function configures AD9361's RX and TX rates. For * a requested TX & RX rate, it sets the interpolation & decimation filters, * and tunes the VCO that feeds the ADCs and DACs. */ double ad9361_device_t::_setup_rates(const double rate) { /* If we make it into this function, then we are tuning to a new rate. * Store the new rate. */ _req_clock_rate = rate; UHD_LOG << boost::format("[ad9361_device_t::_setup_rates] rate=%d\n") % rate; /* Set the decimation and interpolation values in the RX and TX chains. * This also switches filters in / out. Note that all transmitters and * receivers have to be turned on for the calibration portion of * bring-up, and then they will be switched out to reflect the actual * user-requested antenna selections. */ int divfactor = 0; _tfir_factor = 0; _rfir_factor = 0; if (rate < 0.33e6) { // RX1 + RX2 enabled, 3, 2, 2, 4 _regs.rxfilt = B8(11101111); // TX1 + TX2 enabled, 3, 2, 2, 4 _regs.txfilt = B8(11101111); divfactor = 48; _tfir_factor = 4; _rfir_factor = 4; } else if (rate < 0.66e6) { // RX1 + RX2 enabled, 2, 2, 2, 4 _regs.rxfilt = B8(11011111); // TX1 + TX2 enabled, 2, 2, 2, 4 _regs.txfilt = B8(11011111); divfactor = 32; _tfir_factor = 4; _rfir_factor = 4; } else if (rate <= 20e6) { // RX1 + RX2 enabled, 2, 2, 2, 2 _regs.rxfilt = B8(11011110); // TX1 + TX2 enabled, 2, 2, 2, 2 _regs.txfilt = B8(11011110); divfactor = 16; _tfir_factor = 2; _rfir_factor = 2; } else if ((rate > 20e6) && (rate < 23e6)) { // RX1 + RX2 enabled, 3, 2, 2, 2 _regs.rxfilt = B8(11101110); // TX1 + TX2 enabled, 3, 1, 2, 2 _regs.txfilt = B8(11100110); divfactor = 24; _tfir_factor = 2; _rfir_factor = 2; } else if ((rate >= 23e6) && (rate < 41e6)) { // RX1 + RX2 enabled, 2, 2, 2, 2 _regs.rxfilt = B8(11011110); // TX1 + TX2 enabled, 1, 2, 2, 2 _regs.txfilt = B8(11001110); divfactor = 16; _tfir_factor = 2; _rfir_factor = 2; } else if ((rate >= 41e6) && (rate <= 56e6)) { // RX1 + RX2 enabled, 3, 1, 2, 2 _regs.rxfilt = B8(11100110); // TX1 + TX2 enabled, 3, 1, 1, 2 _regs.txfilt = B8(11100010); divfactor = 12; _tfir_factor = 2; _rfir_factor = 2; } else if ((rate > 56e6) && (rate <= 61.44e6)) { // RX1 + RX2 enabled, 3, 1, 1, 2 _regs.rxfilt = B8(11100010); // TX1 + TX2 enabled, 3, 1, 1, 1 _regs.txfilt = B8(11100001); divfactor = 6; _tfir_factor = 1; _rfir_factor = 2; } else { // should never get in here throw uhd::runtime_error("[ad9361_device_t] [_setup_rates] INVALID_CODE_PATH"); } UHD_LOG << boost::format("[ad9361_device_t::_setup_rates] divfactor=%d\n") % divfactor; /* Tune the BBPLL to get the ADC and DAC clocks. */ const double adcclk = _tune_bbvco(rate * divfactor); double dacclk = adcclk; /* The DAC clock must be <= 336e6, and is either the ADC clock or 1/2 the * ADC clock.*/ if (adcclk > 336e6) { /* Make the DAC clock = ADC/2, and bypass the TXFIR. */ _regs.bbpll = _regs.bbpll | 0x08; dacclk = adcclk / 2.0; } else { _regs.bbpll = _regs.bbpll & 0xF7; } /* Set the dividers / interpolators in AD9361. */ _io_iface->poke8(0x002, _regs.txfilt); _io_iface->poke8(0x003, _regs.rxfilt); _io_iface->poke8(0x004, _regs.inputsel); _io_iface->poke8(0x00A, _regs.bbpll); UHD_LOG << boost::format("[ad9361_device_t::_setup_rates] adcclk=%f\n") % adcclk; _baseband_bw = (adcclk / divfactor); /* The Tx & Rx FIR calculate 16 taps per clock cycle. This limits the number of available taps to the ratio of DAC_CLK/ADC_CLK to the input data rate multiplied by 16. For example, if the input data rate is 25 MHz and DAC_CLK is 100 MHz, then the ratio of DAC_CLK to the input data rate is 100/25 or 4. In this scenario, the total number of taps available is 64. Also, whilst the Rx FIR filter always has memory available for 128 taps, the Tx FIR Filter can only support a maximum length of 64 taps in 1x interpolation mode, and 128 taps in 2x & 4x modes. */ const size_t max_tx_taps = std::min( std::min((16 * (int)((dacclk / rate) + 0.5)), 128), (_tfir_factor == 1) ? 64 : 128); const size_t max_rx_taps = std::min((16 * (size_t)((adcclk / rate) + 0.5)), 128); const size_t num_tx_taps = get_num_taps(max_tx_taps); const size_t num_rx_taps = get_num_taps(max_rx_taps); _setup_tx_fir(num_tx_taps,_tfir_factor); _setup_rx_fir(num_rx_taps,_rfir_factor); return _baseband_bw; } /*********************************************************************** * Publicly exported functions to host calls **********************************************************************/ void ad9361_device_t::initialize() { boost::lock_guard lock(_mutex); /* Initialize shadow registers. */ _regs.vcodivs = 0x00; _regs.inputsel = 0x30; _regs.rxfilt = 0x00; _regs.txfilt = 0x00; _regs.bbpll = 0x02; _regs.bbftune_config = 0x1e; _regs.bbftune_mode = 0x1e; /* Initialize private VRQ fields. */ _rx_freq = 0.0; _tx_freq = 0.0; _req_rx_freq = 0.0; _req_tx_freq = 0.0; _baseband_bw = 0.0; _req_clock_rate = 0.0; _req_coreclk = 0.0; _bbpll_freq = 0.0; _adcclock_freq = 0.0; _rx_bbf_tunediv = 0; _curr_gain_table = 0; _rx1_gain = 0; _rx2_gain = 0; _tx1_gain = 0; _tx2_gain = 0; /* Reset the device. */ _io_iface->poke8(0x000, 0x01); _io_iface->poke8(0x000, 0x00); boost::this_thread::sleep(boost::posix_time::milliseconds(20)); /* There is not a WAT big enough for this. */ _io_iface->poke8(0x3df, 0x01); _io_iface->poke8(0x2a6, 0x0e); // Enable master bias _io_iface->poke8(0x2a8, 0x0e); // Set bandgap trim /* Set RFPLL ref clock scale to REFCLK * 2 */ _io_iface->poke8(0x2ab, 0x07); _io_iface->poke8(0x2ac, 0xff); /* Enable clocks. */ switch (_client_params->get_clocking_mode()) { case AD9361_XTAL_N_CLK_PATH: { _io_iface->poke8(0x009, 0x17); } break; case AD9361_XTAL_P_CLK_PATH: { _io_iface->poke8(0x009, 0x07); _io_iface->poke8(0x292, 0x08); _io_iface->poke8(0x293, 0x80); _io_iface->poke8(0x294, 0x00); _io_iface->poke8(0x295, 0x14); } break; default: throw uhd::runtime_error("[ad9361_device_t] NOT IMPLEMENTED"); } boost::this_thread::sleep(boost::posix_time::milliseconds(20)); /* Tune the BBPLL, write TX and RX FIRS. */ _setup_rates(50e6); /* Setup data ports (FDD dual port DDR): * FDD dual port DDR CMOS no swap. * Force TX on one port, RX on the other. */ switch (_client_params->get_digital_interface_mode()) { case AD9361_DDR_FDD_LVCMOS: { _io_iface->poke8(0x010, 0xc8); _io_iface->poke8(0x011, 0x00); _io_iface->poke8(0x012, 0x02); } break; case AD9361_DDR_FDD_LVDS: { _io_iface->poke8(0x010, 0xcc); _io_iface->poke8(0x011, 0x00); _io_iface->poke8(0x012, 0x10); //LVDS Specific _io_iface->poke8(0x03C, 0x23); _io_iface->poke8(0x03D, 0xFF); _io_iface->poke8(0x03E, 0x0F); } break; default: throw uhd::runtime_error("[ad9361_device_t] NOT IMPLEMENTED"); } /* Data delay for TX and RX data clocks */ digital_interface_delays_t timing = _client_params->get_digital_interface_timing(); boost::uint8_t rx_delays = ((timing.rx_clk_delay & 0xF) << 4) | (timing.rx_data_delay & 0xF); boost::uint8_t tx_delays = ((timing.tx_clk_delay & 0xF) << 4) | (timing.tx_data_delay & 0xF); _io_iface->poke8(0x006, rx_delays); _io_iface->poke8(0x007, tx_delays); /* Setup AuxDAC */ _io_iface->poke8(0x018, 0x00); // AuxDAC1 Word[9:2] _io_iface->poke8(0x019, 0x00); // AuxDAC2 Word[9:2] _io_iface->poke8(0x01A, 0x00); // AuxDAC1 Config and Word[1:0] _io_iface->poke8(0x01B, 0x00); // AuxDAC2 Config and Word[1:0] _io_iface->poke8(0x022, 0x4A); // Invert Bypassed LNA _io_iface->poke8(0x023, 0xFF); // AuxDAC Manaul/Auto Control _io_iface->poke8(0x026, 0x00); // AuxDAC Manual Select Bit/GPO Manual Select _io_iface->poke8(0x030, 0x00); // AuxDAC1 Rx Delay _io_iface->poke8(0x031, 0x00); // AuxDAC1 Tx Delay _io_iface->poke8(0x032, 0x00); // AuxDAC2 Rx Delay _io_iface->poke8(0x033, 0x00); // AuxDAC2 Tx Delay /* Setup AuxADC */ _io_iface->poke8(0x00B, 0x00); // Temp Sensor Setup (Offset) _io_iface->poke8(0x00C, 0x00); // Temp Sensor Setup (Temp Window) _io_iface->poke8(0x00D, 0x03); // Temp Sensor Setup (Periodic Measure) _io_iface->poke8(0x00F, 0x04); // Temp Sensor Setup (Decimation) _io_iface->poke8(0x01C, 0x10); // AuxADC Setup (Clock Div) _io_iface->poke8(0x01D, 0x01); // AuxADC Setup (Decimation/Enable) /* Setup control outputs. */ _io_iface->poke8(0x035, 0x01); _io_iface->poke8(0x036, 0xFF); /* Setup GPO */ _io_iface->poke8(0x03a, 0x27); //set delay register _io_iface->poke8(0x020, 0x00); // GPO Auto Enable Setup in RX and TX _io_iface->poke8(0x027, 0x03); // GPO Manual and GPO auto value in ALERT _io_iface->poke8(0x028, 0x00); // GPO_0 RX Delay _io_iface->poke8(0x029, 0x00); // GPO_1 RX Delay _io_iface->poke8(0x02A, 0x00); // GPO_2 RX Delay _io_iface->poke8(0x02B, 0x00); // GPO_3 RX Delay _io_iface->poke8(0x02C, 0x00); // GPO_0 TX Delay _io_iface->poke8(0x02D, 0x00); // GPO_1 TX Delay _io_iface->poke8(0x02E, 0x00); // GPO_2 TX Delay _io_iface->poke8(0x02F, 0x00); // GPO_3 TX Delay _io_iface->poke8(0x261, 0x00); // RX LO power _io_iface->poke8(0x2a1, 0x00); // TX LO power _io_iface->poke8(0x248, 0x0b); // en RX VCO LDO _io_iface->poke8(0x288, 0x0b); // en TX VCO LDO _io_iface->poke8(0x246, 0x02); // pd RX cal Tcf _io_iface->poke8(0x286, 0x02); // pd TX cal Tcf _io_iface->poke8(0x249, 0x8e); // rx vco cal length _io_iface->poke8(0x289, 0x8e); // rx vco cal length _io_iface->poke8(0x23b, 0x80); // set RX MSB?, FIXME 0x89 magic cp _io_iface->poke8(0x27b, 0x80); // "" TX //FIXME 0x88 see above _io_iface->poke8(0x243, 0x0d); // set rx prescaler bias _io_iface->poke8(0x283, 0x0d); // "" TX _io_iface->poke8(0x23d, 0x00); // Clear half VCO cal clock setting _io_iface->poke8(0x27d, 0x00); // Clear half VCO cal clock setting /* The order of the following process is EXTREMELY important. If the * below functions are modified at all, device initialization and * calibration might be broken in the process! */ _io_iface->poke8(0x015, 0x04); // dual synth mode, synth en ctrl en _io_iface->poke8(0x014, 0x05); // use SPI for TXNRX ctrl, to ALERT, TX on _io_iface->poke8(0x013, 0x01); // enable ENSM boost::this_thread::sleep(boost::posix_time::milliseconds(1)); _calibrate_synth_charge_pumps(); _tune_helper(RX, 800e6); _tune_helper(TX, 850e6); _program_mixer_gm_subtable(); _program_gain_table(); _setup_gain_control(); _calibrate_baseband_rx_analog_filter(); _calibrate_baseband_tx_analog_filter(); _calibrate_rx_TIAs(); _calibrate_secondary_tx_filter(); _setup_adc(); _calibrate_tx_quadrature(); _calibrate_rx_quadrature(); // cals done, set PPORT config switch (_client_params->get_digital_interface_mode()) { case AD9361_DDR_FDD_LVCMOS: { _io_iface->poke8(0x012, 0x02); } break; case AD9361_DDR_FDD_LVDS: { _io_iface->poke8(0x012, 0x10); } break; default: throw uhd::runtime_error("[ad9361_device_t] NOT IMPLEMENTED"); } _io_iface->poke8(0x013, 0x01); // Set ENSM FDD bit _io_iface->poke8(0x015, 0x04); // dual synth mode, synth en ctrl en /* Default TX attentuation to 10dB on both TX1 and TX2 */ _io_iface->poke8(0x073, 0x00); _io_iface->poke8(0x074, 0x00); _io_iface->poke8(0x075, 0x00); _io_iface->poke8(0x076, 0x00); /* Setup RSSI Measurements */ _io_iface->poke8(0x150, 0x0E); // RSSI Measurement Duration 0, 1 _io_iface->poke8(0x151, 0x00); // RSSI Measurement Duration 2, 3 _io_iface->poke8(0x152, 0xFF); // RSSI Weighted Multiplier 0 _io_iface->poke8(0x153, 0x00); // RSSI Weighted Multiplier 1 _io_iface->poke8(0x154, 0x00); // RSSI Weighted Multiplier 2 _io_iface->poke8(0x155, 0x00); // RSSI Weighted Multiplier 3 _io_iface->poke8(0x156, 0x00); // RSSI Delay _io_iface->poke8(0x157, 0x00); // RSSI Wait _io_iface->poke8(0x158, 0x0D); // RSSI Mode Select _io_iface->poke8(0x15C, 0x67); // Power Measurement Duration /* Turn on the default RX & TX chains. */ set_active_chains(true, false, false, false); /* Set TXers & RXers on (only works in FDD mode) */ _io_iface->poke8(0x014, 0x21); } /* This function sets the RX / TX rate between AD9361 and the FPGA, and * thus determines the interpolation / decimation required in the FPGA to * achieve the user's requested rate. * * This is the only clock setting function that is exposed to the outside. */ double ad9361_device_t::set_clock_rate(const double req_rate) { boost::lock_guard lock(_mutex); if (req_rate > 61.44e6) { throw uhd::runtime_error("[ad9361_device_t] Requested master clock rate outside range"); } UHD_LOG << boost::format("[ad9361_device_t::set_clock_rate] req_rate=%.10f\n") % req_rate; /* UHD has a habit of requesting the same rate like four times when it * starts up. This prevents that, and any bugs in user code that request * the same rate over and over. */ if (freq_is_nearly_equal(req_rate, _req_clock_rate)) { return _baseband_bw; // IJB. Should this not return req_rate? } /* We must be in the SLEEP / WAIT state to do this. If we aren't already * there, transition the ENSM to State 0. */ boost::uint8_t current_state = _io_iface->peek8(0x017) & 0x0F; switch (current_state) { case 0x05: /* We are in the ALERT state. */ _io_iface->poke8(0x014, 0x21); boost::this_thread::sleep(boost::posix_time::milliseconds(5)); _io_iface->poke8(0x014, 0x00); break; case 0x0A: /* We are in the FDD state. */ _io_iface->poke8(0x014, 0x00); break; default: throw uhd::runtime_error("[ad9361_device_t] [set_clock_rate:1] AD9361 in unknown state"); break; }; /* Store the current chain / antenna selections so that we can restore * them at the end of this routine; all chains will be enabled from * within setup_rates for calibration purposes. */ boost::uint8_t orig_tx_chains = _regs.txfilt & 0xC0; boost::uint8_t orig_rx_chains = _regs.rxfilt & 0xC0; /* Call into the clock configuration / settings function. This is where * all the hard work gets done. */ double rate = _setup_rates(req_rate); UHD_LOG << boost::format("[ad9361_device_t::set_clock_rate] rate=%.10f\n") % rate; /* Transition to the ALERT state and calibrate everything. */ _io_iface->poke8(0x015, 0x04); //dual synth mode, synth en ctrl en _io_iface->poke8(0x014, 0x05); //use SPI for TXNRX ctrl, to ALERT, TX on _io_iface->poke8(0x013, 0x01); //enable ENSM boost::this_thread::sleep(boost::posix_time::milliseconds(1)); _calibrate_synth_charge_pumps(); _tune_helper(RX, _rx_freq); _tune_helper(TX, _tx_freq); _program_mixer_gm_subtable(); _program_gain_table(); _setup_gain_control(); _reprogram_gains(); _calibrate_baseband_rx_analog_filter(); _calibrate_baseband_tx_analog_filter(); _calibrate_rx_TIAs(); _calibrate_secondary_tx_filter(); _setup_adc(); _calibrate_tx_quadrature(); _calibrate_rx_quadrature(); // cals done, set PPORT config switch (_client_params->get_digital_interface_mode()) { case AD9361_DDR_FDD_LVCMOS: { _io_iface->poke8(0x012, 0x02); }break; case AD9361_DDR_FDD_LVDS: { _io_iface->poke8(0x012, 0x10); }break; default: throw uhd::runtime_error("[ad9361_device_t] NOT IMPLEMENTED"); } _io_iface->poke8(0x013, 0x01); // Set ENSM FDD bit _io_iface->poke8(0x015, 0x04); // dual synth mode, synth en ctrl en /* End the function in the same state as the entry state. */ switch (current_state) { case 0x05: /* We are already in ALERT. */ break; case 0x0A: /* Transition back to FDD, and restore the original antenna * / chain selections. */ _regs.txfilt = (_regs.txfilt & 0x3F) | orig_tx_chains; _regs.rxfilt = (_regs.rxfilt & 0x3F) | orig_rx_chains; _io_iface->poke8(0x002, _regs.txfilt); _io_iface->poke8(0x003, _regs.rxfilt); _io_iface->poke8(0x014, 0x21); break; default: throw uhd::runtime_error("[ad9361_device_t] [set_clock_rate:2] AD9361 in unknown state"); break; }; return rate; } /* Set which of the four TX / RX chains provided by AD9361 are active. * * AD9361 provides two sets of chains, Side A and Side B. Each side * provides one TX antenna, and one RX antenna. The B200 maintains the USRP * standard of providing one antenna connection that is both TX & RX, and * one that is RX-only - for each chain. Thus, the possible antenna and * chain selections are: * * B200 Antenna AD9361 Side AD9361 Chain * ------------------------------------------------------------------- * TX / RX1 Side A TX1 (when switched to TX) * TX / RX1 Side A RX1 (when switched to RX) * RX1 Side A RX1 * * TX / RX2 Side B TX2 (when switched to TX) * TX / RX2 Side B RX2 (when switched to RX) * RX2 Side B RX2 */ void ad9361_device_t::set_active_chains(bool tx1, bool tx2, bool rx1, bool rx2) { boost::lock_guard lock(_mutex); /* Clear out the current active chain settings. */ _regs.txfilt = _regs.txfilt & 0x3F; _regs.rxfilt = _regs.rxfilt & 0x3F; /* Turn on the different chains based on the passed parameters. */ if (tx1) { _regs.txfilt = _regs.txfilt | 0x40; } if (tx2) { _regs.txfilt = _regs.txfilt | 0x80; } if (rx1) { _regs.rxfilt = _regs.rxfilt | 0x40; } if (rx2) { _regs.rxfilt = _regs.rxfilt | 0x80; } /* Check for FDD state */ boost::uint8_t set_back_to_fdd = 0; boost::uint8_t ensm_state = _io_iface->peek8(0x017) & 0x0F; if (ensm_state == 0xA) // FDD { /* Put into ALERT state (via the FDD flush state). */ _io_iface->poke8(0x014, 0x01); set_back_to_fdd = 1; } /* Wait for FDD flush state to complete (if necessary) */ while (ensm_state == 0xA || ensm_state == 0xB) ensm_state = _io_iface->peek8(0x017) & 0x0F; /* Turn on / off the chains. */ _io_iface->poke8(0x002, _regs.txfilt); _io_iface->poke8(0x003, _regs.rxfilt); /* Put back into FDD state if necessary */ if (set_back_to_fdd) _io_iface->poke8(0x014, 0x21); } /* Tune the RX or TX frequency. * * This is the publicly-accessible tune function. It makes sure the tune * isn't a redundant request, and if not, passes it on to the class's * internal tune function. * * After tuning, it runs any appropriate calibrations. */ double ad9361_device_t::tune(direction_t direction, const double value) { boost::lock_guard lock(_mutex); if (direction == RX) { if (freq_is_nearly_equal(value, _req_rx_freq)) { return _rx_freq; } } else if (direction == TX) { if (freq_is_nearly_equal(value, _req_tx_freq)) { return _tx_freq; } } else { throw uhd::runtime_error("[ad9361_device_t] [tune] INVALID_CODE_PATH"); } /* If we aren't already in the ALERT state, we will need to return to * the FDD state after tuning. */ int not_in_alert = 0; if ((_io_iface->peek8(0x017) & 0x0F) != 5) { /* Force the device into the ALERT state. */ not_in_alert = 1; _io_iface->poke8(0x014, 0x01); } /* Tune the RF VCO! */ double tune_freq = _tune_helper(direction, value); /* Run any necessary calibrations / setups */ if (direction == RX) { _program_gain_table(); } /* Update the gain settings. */ _reprogram_gains(); /* Run the calibration algorithms. */ _calibrate_tx_quadrature(); _calibrate_rx_quadrature(); /* If we were in the FDD state, return it now. */ if (not_in_alert) { _io_iface->poke8(0x014, 0x21); } return tune_freq; } /* Set the gain of RX1, RX2, TX1, or TX2. * * Note that the 'value' passed to this function is the gain index * for RX. Also note that the RX chains are done in terms of gain, and * the TX chains are done in terms of attenuation. */ double ad9361_device_t::set_gain(direction_t direction, chain_t chain, const double value) { boost::lock_guard lock(_mutex); if (direction == RX) { int gain_index = static_cast(value); /* Clip the gain values to the proper min/max gain values. */ if (gain_index > 76) gain_index = 76; if (gain_index < 0) gain_index = 0; if (chain == CHAIN_1) { _rx1_gain = value; _io_iface->poke8(0x109, gain_index); } else { _rx2_gain = value; _io_iface->poke8(0x10c, gain_index); } return gain_index; } else { /* Setting the below bits causes a change in the TX attenuation word * to immediately take effect. */ _io_iface->poke8(0x077, 0x40); _io_iface->poke8(0x07c, 0x40); /* Each gain step is -0.25dB. Calculate the attenuation necessary * for the requested gain, convert it into gain steps, then write * the attenuation word. Max gain (so zero attenuation) is 89.75. * Ugly values will be written to the attenuation registers if * "value" is out of bounds, so range checking must be performed * outside this function. */ double atten = AD9361_MAX_GAIN - value; boost::uint32_t attenreg = boost::uint32_t(atten * 4); if (chain == CHAIN_1) { _tx1_gain = value; _io_iface->poke8(0x073, attenreg & 0xFF); _io_iface->poke8(0x074, (attenreg >> 8) & 0x01); } else { _tx2_gain = value; _io_iface->poke8(0x075, attenreg & 0xFF); _io_iface->poke8(0x076, (attenreg >> 8) & 0x01); } return AD9361_MAX_GAIN - ((double) (attenreg) / 4); } } void ad9361_device_t::output_test_tone() { boost::lock_guard lock(_mutex); /* Output a 480 kHz tone at 800 MHz */ _io_iface->poke8(0x3F4, 0x0B); _io_iface->poke8(0x3FC, 0xFF); _io_iface->poke8(0x3FD, 0xFF); _io_iface->poke8(0x3FE, 0x3F); } void ad9361_device_t::data_port_loopback(const bool loopback_enabled) { boost::lock_guard lock(_mutex); _io_iface->poke8(0x3F5, (loopback_enabled ? 0x01 : 0x00)); } /* Read back the internal RSSI measurement data. The result is in dB * but not in absolute units. If absolute units are required * a bench calibration should be done. * -0.25dB / bit 9bit resolution.*/ double ad9361_device_t::get_rssi(chain_t chain) { boost::uint32_t reg_rssi = 0; boost::uint8_t lsb_bit_pos = 0; if (chain == CHAIN_1) { reg_rssi = 0x1A7; lsb_bit_pos = 0; }else { reg_rssi = 0x1A9; lsb_bit_pos = 1; } boost::uint8_t msbs = _io_iface->peek8(reg_rssi); boost::uint8_t lsb = ((_io_iface->peek8(0x1AB)) >> lsb_bit_pos) & 0x01; boost::uint16_t val = ((msbs << 1) | lsb); double rssi = (-0.25f * ((double)val)); //-0.25dB/lsb (See Gain Control Users Guide p. 25) return rssi; } }}