mirror of https://github.com/m-labs/artiq
80 lines
2.3 KiB
Python
80 lines
2.3 KiB
Python
from artiq.language.core import kernel, portable, delay
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from artiq.language.units import us, ms
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from artiq.coredevice.shiftreg import ShiftReg
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@portable
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def to_mu(att):
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return round(att*2.0) ^ 0x3f
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@portable
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def from_mu(att_mu):
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return 0.5*(att_mu ^ 0x3f)
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class BaseModAtt:
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def __init__(self, dmgr, rst_n, clk, le, mosi, miso):
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self.rst_n = dmgr.get(rst_n)
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self.shift_reg = ShiftReg(dmgr,
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clk=clk, ser=mosi, latch=le, ser_in=miso, n=8*4)
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@kernel
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def reset(self):
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# HMC's incompetence in digital design and interfaces means that
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# the HMC542 needs a level low on RST_N and then a rising edge
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# on Latch Enable. Their "latch" isn't a latch but a DFF.
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# Of course, it also powers up with a random attenuation, and
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# that cannot be fixed with simple pull-ups/pull-downs.
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self.rst_n.off()
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self.shift_reg.latch.off()
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delay(1*us)
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self.shift_reg.latch.on()
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delay(1*us)
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self.shift_reg.latch.off()
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self.rst_n.on()
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delay(1*us)
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@kernel
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def set_mu(self, att0, att1, att2, att3):
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"""
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Sets the four attenuators on BaseMod.
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The values are in half decibels, between 0 (no attenuation)
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and 63 (31.5dB attenuation).
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"""
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word = (
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(att0 << 2) |
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(att1 << 10) |
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(att2 << 18) |
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(att3 << 26)
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)
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self.shift_reg.set(word)
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@kernel
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def get_mu(self):
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"""
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Retrieves the current settings of the four attenuators on BaseMod.
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"""
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word = self.shift_reg.get()
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att0 = (word >> 2) & 0x3f
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att1 = (word >> 10) & 0x3f
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att2 = (word >> 18) & 0x3f
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att3 = (word >> 26) & 0x3f
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return att0, att1, att2, att3
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@kernel
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def set(self, att0, att1, att2, att3):
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"""
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Sets the four attenuators on BaseMod.
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The values are in decibels.
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"""
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self.set_mu(to_mu(att0), to_mu(att1), to_mu(att2), to_mu(att3))
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@kernel
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def get(self):
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"""
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Retrieves the current settings of the four attenuators on BaseMod.
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The values are in decibels.
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"""
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att0, att1, att2, att3 = self.get_mu()
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return from_mu(att0), from_mu(att1), from_mu(att2), from_mu(att3)
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