diff options
Diffstat (limited to 'host/lib/usrp/dboard/db_sbx_version4.cpp')
| -rw-r--r-- | host/lib/usrp/dboard/db_sbx_version4.cpp | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/host/lib/usrp/dboard/db_sbx_version4.cpp b/host/lib/usrp/dboard/db_sbx_version4.cpp index 12bc9b76e..f091caab7 100644 --- a/host/lib/usrp/dboard/db_sbx_version4.cpp +++ b/host/lib/usrp/dboard/db_sbx_version4.cpp @@ -78,7 +78,6 @@ double sbx_xcvr::sbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar if(ref_freq <= 12.5e6) D = adf4351_regs_t::REFERENCE_DOUBLER_ENABLED; //increase RF divider until acceptable VCO frequency - //start with target_freq*2 because mixer has divide by 2 double vco_freq = target_freq; while (vco_freq < 2.2e9) { vco_freq *= 2; @@ -86,7 +85,7 @@ double sbx_xcvr::sbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar } //use 8/9 prescaler for vco_freq > 3 GHz (pg.18 prescaler) - adf4351_regs_t::prescaler_t prescaler = vco_freq > 3e9 ? adf4351_regs_t::PRESCALER_8_9 : adf4351_regs_t::PRESCALER_4_5; + adf4351_regs_t::prescaler_t prescaler = target_freq > 3e9 ? adf4351_regs_t::PRESCALER_8_9 : adf4351_regs_t::PRESCALER_4_5; /* * The goal here is to loop though possible R dividers, @@ -94,7 +93,7 @@ double sbx_xcvr::sbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar * (frac) dividers. * * Calculate the N and F dividers for each set of values. - * The loop exists when it meets all of the constraints. + * The loop exits when it meets all of the constraints. * The resulting loop values are loaded into the registers. * * from pg.21 @@ -128,7 +127,7 @@ double sbx_xcvr::sbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar //Fractional-N calculation MOD = 4095; //max fractional accuracy - FRAC = int((vco_freq/pfd_freq - N)*MOD); + FRAC = int((target_freq/pfd_freq - N)*MOD); //Reference divide-by-2 for 50% duty cycle // if R even, move one divide by 2 to to regs.reference_divide_by_2 @@ -138,7 +137,7 @@ double sbx_xcvr::sbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar } //actual frequency calculation - actual_freq = double((N + (double(FRAC)/double(MOD)))*ref_freq*(1+int(D))/(R*(1+int(T)))/RFdiv); + actual_freq = double((N + (double(FRAC)/double(MOD)))*ref_freq*(1+int(D))/(R*(1+int(T)))); UHD_LOGV(often) << boost::format("SBX Intermediates: ref=%0.2f, outdiv=%f, fbdiv=%f") % (ref_freq*(1+int(D))/(R*(1+int(T)))) % double(RFdiv*2) % double(N + double(FRAC)/double(MOD)) << std::endl @@ -158,6 +157,9 @@ double sbx_xcvr::sbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar regs.frac_12_bit = FRAC; regs.int_16_bit = N; regs.mod_12_bit = MOD; + regs.clock_divider_12_bit = std::max(1, int(std::ceil(400e-6*pfd_freq/MOD))); + regs.feedback_select = adf4351_regs_t::FEEDBACK_SELECT_DIVIDED; + regs.clock_div_mode = adf4351_regs_t::CLOCK_DIV_MODE_RESYNC_ENABLE; regs.prescaler = prescaler; regs.r_counter_10_bit = R; regs.reference_divide_by_2 = T; |