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b692981c8e
artiq/artiq/coredevice/ad9910.py
Robert Jördens b692981c8e ad9910: add note about red front panel led 
Signed-off-by: Robert Jördens <rj@quartiq.de>
2019-01-22 12:49:42 +01:00

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from numpy import int32, int64
from artiq.language.core import (
kernel, delay, portable, delay_mu, now_mu, at_mu)
from artiq.language.units import us, ms
from artiq.coredevice import spi2 as spi
from artiq.coredevice import urukul
# Work around ARTIQ-Python import machinery
urukul_sta_pll_lock = urukul.urukul_sta_pll_lock
urukul_sta_smp_err = urukul.urukul_sta_smp_err
__all__ = [
"AD9910",
"PHASE_MODE_CONTINUOUS", "PHASE_MODE_ABSOLUTE", "PHASE_MODE_TRACKING",
"RAM_DEST_FTW", "RAM_DEST_POW", "RAM_DEST_ASF", "RAM_DEST_POWASF",
"RAM_MODE_DIRECTSWITCH", "RAM_MODE_RAMPUP", "RAM_MODE_BIDIR_RAMP",
"RAM_MODE_CONT_BIDIR_RAMP", "RAM_MODE_CONT_RAMPUP",
]
_PHASE_MODE_DEFAULT = -1
PHASE_MODE_CONTINUOUS = 0
PHASE_MODE_ABSOLUTE = 1
PHASE_MODE_TRACKING = 2
_AD9910_REG_CFR1 = 0x00
_AD9910_REG_CFR2 = 0x01
_AD9910_REG_CFR3 = 0x02
_AD9910_REG_AUX_DAC = 0x03
_AD9910_REG_IO_UPDATE = 0x04
_AD9910_REG_FTW = 0x07
_AD9910_REG_POW = 0x08
_AD9910_REG_ASF = 0x09
_AD9910_REG_SYNC = 0x0a
_AD9910_REG_RAMP_LIMIT = 0x0b
_AD9910_REG_RAMP_STEP = 0x0c
_AD9910_REG_RAMP_RATE = 0x0d
_AD9910_REG_PROFILE0 = 0x0e
_AD9910_REG_PROFILE1 = 0x0f
_AD9910_REG_PROFILE2 = 0x10
_AD9910_REG_PROFILE3 = 0x11
_AD9910_REG_PROFILE4 = 0x12
_AD9910_REG_PROFILE5 = 0x13
_AD9910_REG_PROFILE6 = 0x14
_AD9910_REG_PROFILE7 = 0x15
_AD9910_REG_RAM = 0x16
# RAM destination
RAM_DEST_FTW = 0
RAM_DEST_POW = 1
RAM_DEST_ASF = 2
RAM_DEST_POWASF = 3
# RAM MODES
RAM_MODE_DIRECTSWITCH = 0
RAM_MODE_RAMPUP = 1
RAM_MODE_BIDIR_RAMP = 2
RAM_MODE_CONT_BIDIR_RAMP = 3
RAM_MODE_CONT_RAMPUP = 4
class AD9910:
"""
AD9910 DDS channel on Urukul.
This class supports a single DDS channel and exposes the DDS,
the digital step attenuator, and the RF switch.
:param chip_select: Chip select configuration. On Urukul this is an
encoded chip select and not "one-hot": 3 to address multiple chips
(as configured through CFG_MASK_NU), 4-7 for individual channels.
:param cpld_device: Name of the Urukul CPLD this device is on.
:param sw_device: Name of the RF switch device. The RF switch is a
TTLOut channel available as the :attr:`sw` attribute of this instance.
:param pll_n: DDS PLL multiplier. The DDS sample clock is
f_ref/clk_div*pll_n where f_ref is the reference frequency and
clk_div is the reference clock divider (both set in the parent
Urukul CPLD instance).
:param pll_en: PLL enable bit, set to 0 to bypass PLL (default: 1).
Note that when bypassing the PLL the red front panel LED may remain on.
:param pll_cp: DDS PLL charge pump setting.
:param pll_vco: DDS PLL VCO range selection.
:param sync_delay_seed: SYNC_IN delay tuning starting value.
To stabilize the SYNC_IN delay tuning, run :meth:`tune_sync_delay` once
and set this to the delay tap number returned (default: -1 to signal no
synchronization and no tuning during :meth:`init`).
:param io_update_delay: IO_UPDATE pulse alignment delay.
To align IO_UPDATE to SYNC_CLK, run :meth:`tune_io_update_delay` and
set this to the delay tap number returned.
"""
kernel_invariants = {"chip_select", "cpld", "core", "bus",
"ftw_per_hz", "io_update_delay", "sysclk_per_mu"}
def __init__(self, dmgr, chip_select, cpld_device, sw_device=None,
pll_n=40, pll_cp=7, pll_vco=5, sync_delay_seed=-1,
io_update_delay=0, pll_en=1):
self.cpld = dmgr.get(cpld_device)
self.core = self.cpld.core
self.bus = self.cpld.bus
assert 3 <= chip_select <= 7
self.chip_select = chip_select
if sw_device:
self.sw = dmgr.get(sw_device)
self.kernel_invariants.add("sw")
clk = self.cpld.refclk/[4, 1, 2, 4][self.cpld.clk_div]
self.pll_en = pll_en
self.pll_n = pll_n
self.pll_vco = pll_vco
self.pll_cp = pll_cp
if pll_en:
sysclk = clk*pll_n
assert clk <= 60e6
assert 12 <= pll_n <= 127
assert 0 <= pll_vco <= 5
vco_min, vco_max = [(370, 510), (420, 590), (500, 700),
(600, 880), (700, 950), (820, 1150)][pll_vco]
assert vco_min <= sysclk/1e6 <= vco_max
assert 0 <= pll_cp <= 7
else:
sysclk = clk
assert sysclk <= 1e9
self.ftw_per_hz = (1 << 32)/sysclk
self.sysclk_per_mu = int(round(sysclk*self.core.ref_period))
if sync_delay_seed >= 0 and not self.cpld.sync_div:
raise ValueError("parent cpld does not drive SYNC")
self.sync_delay_seed = sync_delay_seed
if self.sync_delay_seed >= 0:
assert self.sysclk_per_mu == sysclk*self.core.ref_period
self.io_update_delay = io_update_delay
self.phase_mode = PHASE_MODE_CONTINUOUS
@kernel
def set_phase_mode(self, phase_mode):
r"""Set the default phase mode.
for future calls to :meth:`set` and
:meth:`set_mu`. Supported phase modes are:
* :const:`PHASE_MODE_CONTINUOUS`: the phase accumulator is unchanged
when changing frequency or phase. The DDS phase is the sum of the
phase accumulator and the phase offset. The only discontinuous
changes in the DDS output phase come from changes to the phase
offset. This mode is also knows as "relative phase mode".
:math:`\phi(t) = q(t^\prime) + p + (t - t^\prime) f`
* :const:`PHASE_MODE_ABSOLUTE`: the phase accumulator is reset when
changing frequency or phase. Thus, the phase of the DDS at the
time of the change is equal to the specified phase offset.
:math:`\phi(t) = p + (t - t^\prime) f`
* :const:`PHASE_MODE_TRACKING`: when changing frequency or phase,
the phase accumulator is cleared and the phase offset is offset
by the value the phase accumulator would have if the DDS had been
running at the specified frequency since a given fiducial
time stamp. This is functionally equivalent to
:const:`PHASE_MODE_ABSOLUTE`. The only difference is the fiducial
time stamp. This mode is also known as "coherent phase mode".
The default fiducial time stamp is 0.
:math:`\phi(t) = p + (t - T) f`
Where:
* :math:`\phi(t)`: the DDS output phase
* :math:`q(t) = \phi(t) - p`: DDS internal phase accumulator
* :math:`p`: phase offset
* :math:`f`: frequency
* :math:`t^\prime`: time stamp of setting :math:`p`, :math:`f`
* :math:`T`: fiducial time stamp
* :math:`t`: running time
.. warning:: This setting may become inconsistent when used as part of
a DMA recording. When using DMA, it is recommended to specify the
phase mode explicitly when calling :meth:`set` or :meth:`set_mu`.
"""
self.phase_mode = phase_mode
@kernel
def write32(self, addr, data):
"""Write to 32 bit register.
:param addr: Register address
:param data: Data to be written
"""
self.bus.set_config_mu(urukul.SPI_CONFIG, 8,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write(addr << 24)
self.bus.set_config_mu(urukul.SPI_CONFIG | spi.SPI_END, 32,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write(data)
@kernel
def read32(self, addr):
"""Read from 32 bit register.
:param addr: Register address
"""
self.bus.set_config_mu(urukul.SPI_CONFIG, 8,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write((addr | 0x80) << 24)
self.bus.set_config_mu(
urukul.SPI_CONFIG | spi.SPI_END | spi.SPI_INPUT,
32, urukul.SPIT_DDS_RD, self.chip_select)
self.bus.write(0)
return self.bus.read()
@kernel
def read64(self, addr):
"""Read from 64 bit register.
:param addr: Register address
:return: 64 bit integer register value
"""
self.bus.set_config_mu(
urukul.SPI_CONFIG, 8,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write((addr | 0x80) << 24)
self.bus.set_config_mu(
urukul.SPI_CONFIG | spi.SPI_INPUT, 32,
urukul.SPIT_DDS_RD, self.chip_select)
self.bus.write(0)
self.bus.set_config_mu(
urukul.SPI_CONFIG | spi.SPI_END | spi.SPI_INPUT, 32,
urukul.SPIT_DDS_RD, self.chip_select)
self.bus.write(0)
hi = self.bus.read()
lo = self.bus.read()
return (int64(hi) << 32) | lo
@kernel
def write64(self, addr, data_high, data_low):
"""Write to 64 bit register.
:param addr: Register address
:param data_high: High (MSB) 32 bits of the data
:param data_low: Low (LSB) 32 data bits
"""
self.bus.set_config_mu(urukul.SPI_CONFIG, 8,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write(addr << 24)
self.bus.set_config_mu(urukul.SPI_CONFIG, 32,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write(data_high)
self.bus.set_config_mu(urukul.SPI_CONFIG | spi.SPI_END, 32,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write(data_low)
@kernel
def write_ram(self, data):
"""Write data to RAM.
The profile to write to and the step, start, and end address
need to be configured before and separately using
:meth:`set_profile_ram` and the parent CPLD `set_profile`.
:param data List(int32): Data to be written to RAM.
"""
self.bus.set_config_mu(urukul.SPI_CONFIG, 8, urukul.SPIT_DDS_WR,
self.chip_select)
self.bus.write(_AD9910_REG_RAM << 24)
self.bus.set_config_mu(urukul.SPI_CONFIG, 32,
urukul.SPIT_DDS_WR, self.chip_select)
for i in range(len(data) - 1):
self.bus.write(data[i])
self.bus.set_config_mu(urukul.SPI_CONFIG | spi.SPI_END, 32,
urukul.SPIT_DDS_WR, self.chip_select)
self.bus.write(data[len(data) - 1])
@kernel
def read_ram(self, data):
"""Read data from RAM.
The profile to read from and the step, start, and end address
need to be configured before and separately using
:meth:`set_profile_ram` and the parent CPLD `set_profile`.
:param data List(int32): List to be filled with data read from RAM.
"""
self.bus.set_config_mu(urukul.SPI_CONFIG, 8, urukul.SPIT_DDS_WR,
self.chip_select)
self.bus.write((_AD9910_REG_RAM | 0x80) << 24)
self.bus.set_config_mu(urukul.SPI_CONFIG | spi.SPI_INPUT, 32,
urukul.SPIT_DDS_RD, self.chip_select)
preload = 8
for i in range(len(data) - 1):
self.bus.write(0)
if i >= preload:
data[i - preload] = self.bus.read()
self.bus.set_config_mu(
urukul.SPI_CONFIG | spi.SPI_INPUT | spi.SPI_END, 32,
urukul.SPIT_DDS_RD, self.chip_select)
self.bus.write(0)
for i in range(preload + 1):
data[(len(data) - preload - 1) + i] = self.bus.read()
@kernel
def set_cfr1(self, power_down=0b0000, phase_autoclear=0,
drg_load_lrr=0, drg_autoclear=0,
internal_profile=0, ram_destination=0, ram_enable=0):
"""Set CFR1. See the AD9910 datasheet for parameter meanings.
This method does not pulse IO_UPDATE.
:param power_down: Power down bits.
:param phase_autoclear: Autoclear phase accumulator.
:param drg_load_lrr: Load digital ramp generator LRR.
:param drg_autoclear: Autoclear digital ramp generator.
:param internal_profile: Internal profile control.
:param ram_destination: RAM destination
(:const:`_AD9910_RAM_DEST_FTW`, :const:`_AD9910_RAM_DEST_POW`,
:const:`_AD9910_RAM_DEST_ASF`, :const:`_AD9910_RAM_DEST_POWASF`).
:param ram_enable: RAM mode enable.
"""
self.write32(_AD9910_REG_CFR1,
(ram_enable << 31) |
(ram_destination << 29) |
(internal_profile << 17) |
(drg_load_lrr << 15) |
(drg_autoclear << 14) |
(phase_autoclear << 13) |
(power_down << 4) |
2) # SDIO input only, MSB first
@kernel
def init(self, blind=False):
"""Initialize and configure the DDS.
Sets up SPI mode, confirms chip presence, powers down unused blocks,
configures the PLL, waits for PLL lock. Uses the
IO_UPDATE signal multiple times.
:param blind: Do not read back DDS identity and do not wait for lock.
"""
# Set SPI mode
self.set_cfr1()
self.cpld.io_update.pulse(1*us)
delay(1*ms)
if not blind:
# Use the AUX DAC setting to identify and confirm presence
aux_dac = self.read32(_AD9910_REG_AUX_DAC)
if aux_dac & 0xff != 0x7f:
raise ValueError("Urukul AD9910 AUX_DAC mismatch")
delay(50*us) # slack
# Configure PLL settings and bring up PLL
# enable amplitude scale from profiles
# read effective FTW
# sync timing validation disable (enabled later)
self.write32(_AD9910_REG_CFR2, 0x01010020)
self.cpld.io_update.pulse(1*us)
cfr3 = (0x0807c000 | (self.pll_vco << 24) |
(self.pll_cp << 19) | (self.pll_en << 8) |
(self.pll_n << 1))
self.write32(_AD9910_REG_CFR3, cfr3 | 0x400) # PFD reset
self.cpld.io_update.pulse(1*us)
if self.pll_en:
self.write32(_AD9910_REG_CFR3, cfr3)
self.cpld.io_update.pulse(1*us)
if blind:
delay(100*ms)
else:
# Wait for PLL lock, up to 100 ms
for i in range(100):
sta = self.cpld.sta_read()
lock = urukul_sta_pll_lock(sta)
delay(1*ms)
if lock & (1 << self.chip_select - 4):
break
if i >= 100 - 1:
raise ValueError("PLL lock timeout")
delay(10*us) # slack
if self.sync_delay_seed >= 0:
self.tune_sync_delay(self.sync_delay_seed)
delay(1*ms)
@kernel
def power_down(self, bits=0b1111):
"""Power down DDS.
:param bits: Power down bits, see datasheet
"""
self.set_cfr1(power_down=bits)
self.cpld.io_update.pulse(1*us)
# KLUDGE: ref_time_mu default argument is explicitly marked int64() to avoid
# silent truncation of explicitly passed timestamps. (Compiler bug?)
@kernel
def set_mu(self, ftw, pow_=0, asf=0x3fff, phase_mode=_PHASE_MODE_DEFAULT,
ref_time_mu=int64(-1), profile=0):
"""Set profile 0 data in machine units.
This uses machine units (FTW, POW, ASF). The frequency tuning word
width is 32, the phase offset word width is 16, and the amplitude
scale factor width is 12.
After the SPI transfer, the shared IO update pin is pulsed to
activate the data.
.. seealso: :meth:`set_phase_mode` for a definition of the different
phase modes.
:param ftw: Frequency tuning word: 32 bit.
:param pow_: Phase tuning word: 16 bit unsigned.
:param asf: Amplitude scale factor: 14 bit unsigned.
:param phase_mode: If specified, overrides the default phase mode set
by :meth:`set_phase_mode` for this call.
:param ref_time_mu: Fiducial time used to compute absolute or tracking
phase updates. In machine units as obtained by `now_mu()`.
:param profile: Profile number to set (0-7, default: 0).
:return: Resulting phase offset word after application of phase
tracking offset. When using :const:`PHASE_MODE_CONTINUOUS` in
subsequent calls, use this value as the "current" phase.
"""
if phase_mode == _PHASE_MODE_DEFAULT:
phase_mode = self.phase_mode
# Align to coarse RTIO which aligns SYNC_CLK. I.e. clear fine TSC
# This will not cause a collision or sequence error.
at_mu(now_mu() & ~7)
if phase_mode != PHASE_MODE_CONTINUOUS:
# Auto-clear phase accumulator on IO_UPDATE.
# This is active already for the next IO_UPDATE
self.set_cfr1(phase_autoclear=1)
if phase_mode == PHASE_MODE_TRACKING and ref_time_mu < 0:
# set default fiducial time stamp
ref_time_mu = 0
if ref_time_mu >= 0:
# 32 LSB are sufficient.
# Also no need to use IO_UPDATE time as this
# is equivalent to an output pipeline latency.
dt = int32(now_mu()) - int32(ref_time_mu)
pow_ += dt*ftw*self.sysclk_per_mu >> 16
self.write64(_AD9910_REG_PROFILE0 + profile,
(asf << 16) | (pow_ & 0xffff), ftw)
delay_mu(int64(self.io_update_delay))
self.cpld.io_update.pulse_mu(8) # assumes 8 mu > t_SYN_CCLK
at_mu(now_mu() & ~7) # clear fine TSC again
if phase_mode != PHASE_MODE_CONTINUOUS:
self.set_cfr1()
# future IO_UPDATE will activate
return pow_
@kernel
def set_profile_ram(self, start, end, step=1, profile=0, nodwell_high=0,
zero_crossing=0, mode=1):
"""Set the RAM profile settings.
:param start: Profile start address in RAM.
:param end: Profile end address in RAM (last address).
:param step: Profile address step size (default: 1).
:param profile: Profile index (0 to 7) (default: 0).
:param nodwell_high: No-dwell high bit (default: 0,
see AD9910 documentation).
:param zero_crossing: Zero crossing bit (default: 0,
see AD9910 documentation).
:param mode: Profile RAM mode (:const:`RAM_MODE_DIRECTSWITCH`,
:const:`RAM_MODE_RAMPUP`, :const:`RAM_MODE_BIDIR_RAMP`,
:const:`RAM_MODE_CONT_BIDIR_RAMP`, or
:const:`RAM_MODE_CONT_RAMPUP`, default:
:const:`RAM_MODE_RAMPUP`)
"""
hi = (step << 8) | (end >> 2)
lo = ((end << 30) | (start << 14) | (nodwell_high << 5) |
(zero_crossing << 3) | mode)
self.write64(_AD9910_REG_PROFILE0 + profile, hi, lo)
@kernel
def set_ftw(self, ftw):
self.write32(_AD9910_REG_FTW, ftw)
@kernel
def set_asf(self, asf):
self.write32(_AD9910_REG_ASF, asf)
@kernel
def set_pow(self, pow_):
self.write32(_AD9910_REG_POW, pow_)
@portable(flags={"fast-math"})
def frequency_to_ftw(self, frequency):
"""Return the frequency tuning word corresponding to the given
frequency.
"""
return int32(round(self.ftw_per_hz*frequency))
@portable(flags={"fast-math"})
def ftw_to_frequency(self, ftw):
"""Return the frequency corresponding to the given frequency tuning
word.
"""
return ftw / self.ftw_per_hz
@portable(flags={"fast-math"})
def turns_to_pow(self, turns):
"""Return the phase offset word corresponding to the given phase
in turns."""
return int32(round(turns*0x10000))
@portable(flags={"fast-math"})
def pow_to_turns(self, pow_):
"""Return the phase in turns corresponding to a given phase offset
word."""
return pow_/0x10000
@portable(flags={"fast-math"})
def amplitude_to_asf(self, amplitude):
"""Return amplitude scale factor corresponding to given fractional
amplitude."""
return int32(round(amplitude*0x3ffe))
@portable(flags={"fast-math"})
def asf_to_amplitude(self, asf):
"""Return amplitude as a fraction of full scale corresponding to given
amplitude scale factor."""
return asf / float(0x3ffe)
@kernel
def set_frequency(self, frequency):
return self.set_ftw(self.frequency_to_ftw(frequency))
@kernel
def set_amplitude(self, amplitude):
return self.set_asf(self.amplitude_to_asf(amplitude))
@kernel
def set_phase(self, turns):
return self.set_pow(self.turns_to_pow(turns))
@kernel
def set(self, frequency, phase=0.0, amplitude=1.0,
phase_mode=_PHASE_MODE_DEFAULT, ref_time_mu=int64(-1), profile=0):
"""Set profile 0 data in SI units.
.. seealso:: :meth:`set_mu`
:param frequency: Frequency in Hz
:param phase: Phase tuning word in turns
:param amplitude: Amplitude in units of full scale
:param phase_mode: Phase mode constant
:param ref_time_mu: Fiducial time stamp in machine units
:param profile: Profile to affect
:return: Resulting phase offset in turns
"""
return self.pow_to_turns(self.set_mu(
self.frequency_to_ftw(frequency), self.turns_to_pow(phase),
self.amplitude_to_asf(amplitude), phase_mode, ref_time_mu, profile))
@kernel
def set_att_mu(self, att):
"""Set digital step attenuator in machine units.
.. seealso:: :meth:`artiq.coredevice.urukul.CPLD.set_att_mu`
:param att: Attenuation setting, 8 bit digital.
"""
self.cpld.set_att_mu(self.chip_select - 4, att)
@kernel
def set_att(self, att):
"""Set digital step attenuator in SI units.
.. seealso:: :meth:`artiq.coredevice.urukul.CPLD.set_att`
:param att: Attenuation in dB.
"""
self.cpld.set_att(self.chip_select - 4, att)
@kernel
def cfg_sw(self, state):
"""Set CPLD CFG RF switch state. The RF switch is controlled by the
logical or of the CPLD configuration shift register
RF switch bit and the SW TTL line (if used).
:param state: CPLD CFG RF switch bit
"""
self.cpld.cfg_sw(self.chip_select - 4, state)
@kernel
def set_sync(self, in_delay, window):
"""Set the relevant parameters in the multi device synchronization
register. See the AD9910 datasheet for details. The SYNC clock
generator preset value is set to zero, and the SYNC_OUT generator is
disabled.
:param in_delay: SYNC_IN delay tap (0-31) in steps of ~75ps
:param window: Symmetric SYNC_IN validation window (0-15) in
steps of ~75ps for both hold and setup margin.
"""
self.write32(_AD9910_REG_SYNC,
(window << 28) | # SYNC S/H validation delay
(1 << 27) | # SYNC receiver enable
(0 << 26) | # SYNC generator disable
(0 << 25) | # SYNC generator SYS rising edge
(0 << 18) | # SYNC preset
(0 << 11) | # SYNC output delay
(in_delay << 3)) # SYNC receiver delay
@kernel
def clear_smp_err(self):
"""Clear the SMP_ERR flag and enables SMP_ERR validity monitoring.
Violations of the SYNC_IN sample and hold margins will result in
SMP_ERR being asserted. This then also activates the red LED on
the respective Urukul channel.
Also modifies CFR2.
"""
self.write32(_AD9910_REG_CFR2, 0x01010020) # clear SMP_ERR
self.cpld.io_update.pulse(1*us)
self.write32(_AD9910_REG_CFR2, 0x01010000) # enable SMP_ERR
self.cpld.io_update.pulse(1*us)
@kernel
def tune_sync_delay(self, search_seed=15):
"""Find a stable SYNC_IN delay.
This method first locates a valid SYNC_IN delay at zero validation
window size (setup/hold margin) by scanning around `search_seed`. It
then looks for similar valid delays at successively larger validation
window sizes until none can be found. It then decreases the validation
window a bit to provide some slack and stability and returns the
optimal values.
This method and :meth:`tune_io_update_delay` can be run in any order.
:param search_seed: Start value for valid SYNC_IN delay search.
Defaults to 15 (half range).
:return: Tuple of optimal delay and window size.
"""
if not self.cpld.sync_div:
raise ValueError("parent cpld does not drive SYNC")
search_span = 31
# FIXME https://github.com/sinara-hw/Urukul/issues/16
# should both be 2-4 once kasli sync_in jitter is identified
min_window = 0
margin = 1 # 1*75ps setup and hold
for window in range(16):
next_seed = -1
for in_delay in range(search_span - 2*window):
# alternate search direction around search_seed
if in_delay & 1:
in_delay = -in_delay
in_delay = search_seed + (in_delay >> 1)
if in_delay < 0 or in_delay > 31:
continue
self.set_sync(in_delay, window)
self.clear_smp_err()
# integrate SMP_ERR statistics for a few hundred cycles
delay(100*us)
err = urukul_sta_smp_err(self.cpld.sta_read())
delay(100*us) # slack
if not (err >> (self.chip_select - 4)) & 1:
next_seed = in_delay
break
if next_seed >= 0: # valid delay found, scan next window
search_seed = next_seed
continue
elif window > min_window:
# no valid delay found here, roll back and add margin
window = max(min_window, window - 1 - margin)
self.set_sync(search_seed, window)
self.clear_smp_err()
delay(100*us) # slack
return search_seed, window
else:
break
raise ValueError("no valid window/delay")
@kernel
def measure_io_update_alignment(self, delay_start, delay_stop):
"""Use the digital ramp generator to locate the alignment between
IO_UPDATE and SYNC_CLK.
The ramp generator is set up to a linear frequency ramp
(dFTW/t_SYNC_CLK=1) and started at a coarse RTIO time stamp plus
`delay_start` and stopped at a coarse RTIO time stamp plus
`delay_stop`.
:param delay_start: Start IO_UPDATE delay in machine units.
:param delay_stop: Stop IO_UPDATE delay in machine units.
:return: Odd/even SYNC_CLK cycle indicator.
"""
# set up DRG
self.set_cfr1(drg_load_lrr=1, drg_autoclear=1)
# DRG -> FTW, DRG enable
self.write32(_AD9910_REG_CFR2, 0x01090000)
# no limits
self.write64(_AD9910_REG_RAMP_LIMIT, -1, 0)
# DRCTL=0, dt=1 t_SYNC_CLK
self.write32(_AD9910_REG_RAMP_RATE, 0x00010000)
# dFTW = 1, (work around negative slope)
self.write64(_AD9910_REG_RAMP_STEP, -1, 0)
# delay io_update after RTIO edge
t = now_mu() + 8 & ~7
at_mu(t + delay_start)
# assumes a maximum t_SYNC_CLK period
self.cpld.io_update.pulse_mu(16 - delay_start) # realign
# disable DRG autoclear and LRR on io_update
self.set_cfr1()
# stop DRG
self.write64(_AD9910_REG_RAMP_STEP, 0, 0)
at_mu(t + 0x1000 + delay_stop)
self.cpld.io_update.pulse_mu(16 - delay_stop) # realign
ftw = self.read32(_AD9910_REG_FTW) # read out effective FTW
delay(100*us) # slack
# disable DRG
self.write32(_AD9910_REG_CFR2, 0x01010000)
self.cpld.io_update.pulse_mu(8)
return ftw & 1
@kernel
def tune_io_update_delay(self):
"""Find a stable IO_UPDATE delay alignment.
Scan through increasing IO_UPDATE delays until a delay is found that
lets IO_UPDATE be registered in the next SYNC_CLK cycle. Return a
IO_UPDATE delay that is as far away from that SYNC_CLK edge
as possible.
This method assumes that the IO_UPDATE TTLOut device has one machine
unit resolution (SERDES).
This method and :meth:`tune_sync_delay` can be run in any order.
:return: Stable IO_UPDATE delay to be passed to the constructor
:class:`AD9910` via the device database.
"""
period = self.sysclk_per_mu * 4 # SYNC_CLK period
repeat = 100
for i in range(period):
t = 0
# check whether the sync edge is strictly between i, i+2
for j in range(repeat):
t += self.measure_io_update_alignment(i, i + 2)
if t != 0: # no certain edge
continue
# check left/right half: i,i+1 and i+1,i+2
t1 = [0, 0]
for j in range(repeat):
t1[0] += self.measure_io_update_alignment(i, i + 1)
t1[1] += self.measure_io_update_alignment(i + 1, i + 2)
if ((t1[0] == 0 and t1[1] == 0) or
(t1[0] == repeat and t1[1] == repeat)):
# edge is not close to i + 1, can't interpret result
raise ValueError(
"no clear IO_UPDATE-SYNC_CLK alignment edge found")
else:
# the good delay is period//2 after the edge
return (i + 1 + period//2) & (period - 1)
raise ValueError("no IO_UPDATE-SYNC_CLK alignment edge found")
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