Source code for artiq.coredevice.ttl

"""
Drivers for TTL signals on RTIO.

TTL channels (including the clock generator) all support output event
replacement. For example, pulses of "zero" length (e.g. :meth:`TTLInOut.on`
immediately followed by :meth:`TTLInOut.off`, without a delay) are suppressed.
"""

import numpy

from artiq.language.core import *
from artiq.language.types import *
from artiq.coredevice.rtio import (rtio_output, rtio_input_timestamp,
                                   rtio_input_data)
from artiq.coredevice.exceptions import RTIOOverflow


# RTIO TTL address map:
# 0 Output level
# 1 Output enable
# 2 Set input sensitivity
# 3 Set input sensitivity and sample


[docs]class TTLOut: """RTIO TTL output driver. This should be used with output-only channels. :param channel: channel number """ kernel_invariants = {"core", "channel"} def __init__(self, dmgr, channel, core_device="core"): self.core = dmgr.get(core_device) self.channel = channel @kernel def output(self): pass @kernel def set_o(self, o): rtio_output(now_mu(), self.channel, 0, 1 if o else 0) @kernel
[docs] def on(self): """Sets the output to a logic high state at the current position of the time cursor. The time cursor is not modified by this function.""" self.set_o(True)
@kernel
[docs] def off(self): """Set the output to a logic low state at the current position of the time cursor. The time cursor is not modified by this function.""" self.set_o(False)
@kernel
[docs] def pulse_mu(self, duration): """Pulse the output high for the specified duration (in machine units). The time cursor is advanced by the specified duration.""" self.on() delay_mu(duration) self.off()
@kernel
[docs] def pulse(self, duration): """Pulse the output high for the specified duration (in seconds). The time cursor is advanced by the specified duration.""" self.on() delay(duration) self.off()
[docs]class TTLInOut: """RTIO TTL input/output driver. In output mode, provides functions to set the logic level on the signal. In input mode, provides functions to analyze the incoming signal, with real-time gating to prevent overflows. RTIO TTLs supports zero-length transition suppression. For example, if two pulses are emitted back-to-back with no delay between them, they will be merged into a single pulse with a duration equal to the sum of the durations of the original pulses. This should be used with bidirectional channels. Note that the channel is in input mode by default. If you need to drive a signal, you must call :meth:`output`. If the channel is in output mode most of the time in your setup, it is a good idea to call :meth:`output` in the startup kernel. There are three input APIs: gating, sampling and watching. When one API is active (e.g. the gate is open, or the input events have not been fully read out), another API must not be used simultaneously. :param channel: channel number """ kernel_invariants = {"core", "channel"} def __init__(self, dmgr, channel, core_device="core"): self.core = dmgr.get(core_device) self.channel = channel @kernel def set_oe(self, oe): rtio_output(now_mu(), self.channel, 1, 1 if oe else 0) @kernel
[docs] def output(self): """Set the direction to output at the current position of the time cursor. There must be a delay of at least one RTIO clock cycle before any other command can be issued.""" self.set_oe(True)
@kernel
[docs] def input(self): """Set the direction to input at the current position of the time cursor. There must be a delay of at least one RTIO clock cycle before any other command can be issued.""" self.set_oe(False)
@kernel def set_o(self, o): rtio_output(now_mu(), self.channel, 0, 1 if o else 0) @kernel
[docs] def on(self): """Set the output to a logic high state at the current position of the time cursor. The channel must be in output mode. The time cursor is not modified by this function.""" self.set_o(True)
@kernel
[docs] def off(self): """Set the output to a logic low state at the current position of the time cursor. The channel must be in output mode. The time cursor is not modified by this function.""" self.set_o(False)
@kernel
[docs] def pulse_mu(self, duration): """Pulses the output high for the specified duration (in machine units). The time cursor is advanced by the specified duration.""" self.on() delay_mu(duration) self.off()
@kernel
[docs] def pulse(self, duration): """Pulses the output high for the specified duration (in seconds). The time cursor is advanced by the specified duration.""" self.on() delay(duration) self.off()
# Input API: gating @kernel def _set_sensitivity(self, value): rtio_output(now_mu(), self.channel, 2, value) @kernel
[docs] def gate_rising_mu(self, duration): """Register rising edge events for the specified duration (in machine units). The time cursor is advanced by the specified duration. :return: The timeline cursor at the end of the gate window, for convenience when used with :meth:`count`/:meth:`timestamp_mu`. """ self._set_sensitivity(1) delay_mu(duration) self._set_sensitivity(0) return now_mu()
@kernel
[docs] def gate_falling_mu(self, duration): """Register falling edge events for the specified duration (in machine units). The time cursor is advanced by the specified duration. :return: The timeline cursor at the end of the gate window, for convenience when used with :meth:`count`/:meth:`timestamp_mu`. """ self._set_sensitivity(2) delay_mu(duration) self._set_sensitivity(0) return now_mu()
@kernel
[docs] def gate_both_mu(self, duration): """Register both rising and falling edge events for the specified duration (in machine units). The time cursor is advanced by the specified duration. :return: The timeline cursor at the end of the gate window, for convenience when used with :meth:`count`/:meth:`timestamp_mu`. """ self._set_sensitivity(3) delay_mu(duration) self._set_sensitivity(0) return now_mu()
@kernel
[docs] def gate_rising(self, duration): """Register rising edge events for the specified duration (in seconds). The time cursor is advanced by the specified duration. :return: The timeline cursor at the end of the gate window, for convenience when used with :meth:`count`/:meth:`timestamp_mu`. """ self._set_sensitivity(1) delay(duration) self._set_sensitivity(0) return now_mu()
@kernel
[docs] def gate_falling(self, duration): """Register falling edge events for the specified duration (in seconds). The time cursor is advanced by the specified duration. :return: The timeline cursor at the end of the gate window, for convenience when used with :meth:`count`/:meth:`timestamp_mu`. """ self._set_sensitivity(2) delay(duration) self._set_sensitivity(0) return now_mu()
@kernel
[docs] def gate_both(self, duration): """Register both rising and falling edge events for the specified duration (in seconds). The time cursor is advanced by the specified duration. :return: The timeline cursor at the end of the gate window, for convenience when used with :meth:`count`/:meth:`timestamp_mu`. """ self._set_sensitivity(3) delay(duration) self._set_sensitivity(0) return now_mu()
@kernel
[docs] def count(self, up_to_timestamp_mu): """Consume RTIO input events until the hardware timestamp counter has reached the specified timestamp and return the number of observed events. This function does not interact with the timeline cursor. See the ``gate_*()`` family of methods to select the input transitions that generate events, and :meth:`timestamp_mu` to obtain the timestamp of the first event rather than an accumulated count. :param up_to_timestamp_mu: The timestamp up to which execution is blocked, that is, up to which input events are guaranteed to be taken into account. (Events with later timestamps might still be registered if they are already available.) :return: The number of events before the timeout elapsed (0 if none observed). Examples: To count events on channel ``ttl_input``, up to the current timeline position:: ttl_input.count(now_mu()) If other events are scheduled between the end of the input gate period and when the number of events is counted, using ``now_mu()`` as timeout consumes an unnecessary amount of timeline slack. In such cases, it can be beneficial to pass a more precise timestamp, for example:: gate_end_mu = ttl_input.gate_rising(100 * us) # Schedule a long pulse sequence, represented here by a delay. delay(10 * ms) # Get number of rising edges. This will block until the end of # the gate window, but does not wait for the long pulse sequence # afterwards, thus (likely) completing with a large amount of # slack left. num_rising_edges = ttl_input.count(gate_end_mu) The ``gate_*()`` family of methods return the cursor at the end of the window, allowing this to be expressed in a compact fashion:: ttl_input.count(ttl_input.gate_rising(100 * us)) """ count = 0 while rtio_input_timestamp(up_to_timestamp_mu, self.channel) >= 0: count += 1 return count
@kernel
[docs] def timestamp_mu(self, up_to_timestamp_mu): """Return the timestamp of the next RTIO input event, or -1 if the hardware timestamp counter reaches the given value before an event is received. This function does not interact with the timeline cursor. See the ``gate_*()`` family of methods to select the input transitions that generate events, and :meth:`count` for usage examples. :param up_to_timestamp_mu: The timestamp up to which execution is blocked, that is, up to which input events are guaranteed to be taken into account. (Events with later timestamps might still be registered if they are already available.) :return: The timestamp (in machine units) of the first event received; -1 on timeout. """ return rtio_input_timestamp(up_to_timestamp_mu, self.channel)
# Input API: sampling @kernel
[docs] def sample_input(self): """Instructs the RTIO core to read the value of the TTL input at the position of the time cursor. The time cursor is not modified by this function.""" rtio_output(now_mu(), self.channel, 3, 0)
@kernel
[docs] def sample_get(self): """Returns the value of a sample previously obtained with :meth:`sample_input`. Multiple samples may be queued (using multiple calls to :meth:`sample_input`) into the RTIO FIFOs and subsequently read out using multiple calls to this function. This function does not interact with the time cursor.""" return rtio_input_data(self.channel)
@kernel
[docs] def sample_get_nonrt(self): """Convenience function that obtains the value of a sample at the position of the time cursor, breaks realtime, and returns the sample value.""" self.sample_input() r = self.sample_get() self.core.break_realtime() return r
# Input API: watching @kernel
[docs] def watch_stay_on(self): """Checks that the input is at a high level at the position of the time cursor and keep checking until :meth:`watch_done` is called. Returns ``True`` if the input is high. A call to this function must always be followed by an eventual call to :meth:`watch_done` (use e.g. a try/finally construct to ensure this). The time cursor is not modified by this function. """ rtio_output(now_mu(), self.channel, 3, 2) # gate falling return rtio_input_data(self.channel) == 1
@kernel
[docs] def watch_stay_off(self): """Like :meth:`watch_stay_on`, but for low levels.""" rtio_output(now_mu(), self.channel, 3, 1) # gate rising return rtio_input_data(self.channel) == 0
@kernel
[docs] def watch_done(self): """Stop watching the input at the position of the time cursor. Returns ``True`` if the input has not changed state while it was being watched. The time cursor is not modified by this function. This function always makes the slack negative. """ rtio_output(now_mu(), self.channel, 2, 0) success = True try: while rtio_input_timestamp(now_mu(), self.channel) != -1: success = False except RTIOOverflow: success = False return success
[docs]class TTLClockGen: """RTIO TTL clock generator driver. This should be used with TTL channels that have a clock generator built into the gateware (not compatible with regular TTL channels). The time cursor is not modified by any function in this class. :param channel: channel number :param acc_width: accumulator width in bits """ kernel_invariants = {"core", "channel", "acc_width"} def __init__(self, dmgr, channel, acc_width=24, core_device="core"): self.core = dmgr.get(core_device) self.channel = channel self.acc_width = numpy.int64(acc_width) @portable
[docs] def frequency_to_ftw(self, frequency): """Returns the frequency tuning word corresponding to the given frequency. """ return round(2**self.acc_width*frequency*self.core.coarse_ref_period)
@portable
[docs] def ftw_to_frequency(self, ftw): """Returns the frequency corresponding to the given frequency tuning word. """ return ftw/self.core.coarse_ref_period/2**self.acc_width
@kernel
[docs] def set_mu(self, frequency): """Set the frequency of the clock, in machine units, at the current position of the time cursor. This also sets the phase, as the time of the first generated rising edge corresponds to the time of the call. The clock generator contains a 24-bit phase accumulator operating on the RTIO clock. At each RTIO clock tick, the frequency tuning word is added to the phase accumulator. The most significant bit of the phase accumulator is connected to the TTL line. Setting the frequency tuning word has the additional effect of setting the phase accumulator to 0x800000. Due to the way the clock generator operates, frequency tuning words that are not powers of two cause jitter of one RTIO clock cycle at the output.""" rtio_output(now_mu(), self.channel, 0, frequency)
@kernel
[docs] def set(self, frequency): """Like :meth:`set_mu`, but using Hz.""" self.set_mu(self.frequency_to_ftw(frequency))
@kernel
[docs] def stop(self): """Stop the toggling of the clock and set the output level to 0.""" self.set_mu(0)