diff options
| -rw-r--r-- | mpm/python/usrp_mpm/chips/adf400x.py | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/mpm/python/usrp_mpm/chips/adf400x.py b/mpm/python/usrp_mpm/chips/adf400x.py index 4a33a33a9..5f200f30f 100644 --- a/mpm/python/usrp_mpm/chips/adf400x.py +++ b/mpm/python/usrp_mpm/chips/adf400x.py @@ -34,17 +34,20 @@ class ADF400x(object): # Instantiate our own copy of the register mapping and update some values self.adf400x_regs = ADF400xRegs() - self.adf400x_regs.ref_counter = 1 + # N counter = fVCO/PFD + self.adf400x_regs.n_counter = 4 self.adf400x_regs.charge_pump_current_1 = 7 self.adf400x_regs.charge_pump_current_2 = 7 + # Set MUXOUT to Digital Lock Detect self.adf400x_regs.muxout = ADF400xRegs.MUXOUT_DLD self.adf400x_regs.counter_reset = ADF400xRegs.COUNTER_RESET_NORMAL self.adf400x_regs.phase_detector_polarity = ADF400xRegs.PHASE_DETECTOR_POLARITY_POS - self.adf400x_regs.charge_pump_mode = ADF400xRegs.CHARGE_PUMP_TRISTATE + # Turn on Charge Pump + self.adf400x_regs.charge_pump_mode = ADF400xRegs.CHARGE_PUMP_NORMAL # Set the N counter if freq is None: freq = DEFAULT_REF_CLOCK_FREQ - self._set_n_counter(freq) + self._set_ref_counter(freq) # Now initialize the ADF400x self.program_regs() @@ -76,19 +79,24 @@ class ADF400x(object): self.adf400x_regs.charge_pump_mode = ADF400xRegs.CHARGE_PUMP_TRISTATE self.program_regs() - def _set_n_counter(self, freq): - n_counter = int(BASE_REF_CLOCK_FREQ / freq) - if self.adf400x_regs.n_counter == n_counter: - self.log.trace("No change to N counter value ({}); returning early".format(n_counter)) + def _set_ref_counter(self, freq): + """ + Set R Counter based on reference frequency + """ + # Calculate R counter fVCO = N * (fREF/R) + ref_counter = int(self.adf400x_regs.n_counter * freq / BASE_REF_CLOCK_FREQ) + if self.adf400x_regs.ref_counter == ref_counter: + self.log.trace("No change to ref counter value ({}); \ + returning early".format(ref_counter)) return - self.log.trace("Setting N counter to {}".format(n_counter)) + self.log.trace("Setting ref counter to {}".format(ref_counter)) # Limits from the datasheet - assert 1 <= n_counter <= 8191 - self.adf400x_regs.n_counter = n_counter + assert 1 <= ref_counter <= 16383 + self.adf400x_regs.ref_counter = ref_counter def set_ref_freq(self, freq): """Set the input reference frequency""" - self._set_n_counter(freq) + self._set_ref_counter(freq) self.program_regs() |