# 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

# 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", "gate_latency_mu"}

def __init__(self, dmgr, channel, gate_latency_mu=None,
core_device="core"):
self.core = dmgr.get(core_device)
self.channel = channel
# With TTLs inputs, the gate control is connected to a high-latency
# path through SED. When looking at the RTIO counter to determine if
# the gate has closed, we need to take this latency into account.
# See: https://github.com/m-labs/artiq/issues/1137
if gate_latency_mu is None:
gate_latency_mu = 13*self.core.ref_multiplier
self.gate_latency_mu = gate_latency_mu

@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.gate_latency_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

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.gate_latency_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.gate_latency_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)