forked from M-Labs/artiq
73 lines
2.3 KiB
Python
73 lines
2.3 KiB
Python
from artiq.language.core import *
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from artiq.language.units import *
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from artiq.devices import rtio_core
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class DDS(AutoContext):
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"""Core device Direct Digital Synthesis (DDS) driver.
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Controls DDS devices managed directly by the core device's runtime. It also
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uses a RTIO channel (through :class:`artiq.devices.rtio_core.RTIOOut`) to
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control a RF switch that gates the output of the DDS device.
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:param dds_sysclk: DDS system frequency, used for computing the frequency
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tuning words.
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:param reg_channel: channel number of the DDS device to control.
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:param rtio_channel: RTIO channel number of the RF switch associated with
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the DDS device.
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"""
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parameters = "dds_sysclk reg_channel rtio_channel"
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def build(self):
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self.previous_frequency = 0*MHz
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self.sw = rtio_core.RTIOOut(self, channel=self.rtio_channel)
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kernel_attr = "previous_frequency"
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@kernel
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def on(self, frequency):
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"""Sets the DDS channel to the specified frequency and turns it on.
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If the DDS channel was already on, a real-time frequency update is
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performed.
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"""
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if self.previous_frequency != frequency:
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if self.sw.previous_timestamp != time_to_cycles(now()):
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self.sw.sync()
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if self.sw.previous_value:
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# Channel is already on.
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# Precise timing of frequency change is required.
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fud_time = time_to_cycles(now())
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else:
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# Channel is off.
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# Use soft timing on FUD to prevent conflicts when
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# reprogramming several channels that need to be turned on at
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# the same time.
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fud_time = -1
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syscall("dds_program", self.reg_channel,
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int(2**32*frequency/self.dds_sysclk),
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fud_time)
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self.previous_frequency = frequency
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self.sw.on()
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@kernel
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def off(self):
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"""Turns the DDS channel off.
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"""
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self.sw.off()
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@kernel
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def pulse(self, frequency, duration):
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"""Pulses the DDS channel for the specified duration at the specified
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frequency.
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Equivalent to a ``on``, ``delay``, ``off`` sequence.
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"""
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self.on(frequency)
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delay(duration)
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self.off()
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