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fastino: make driver filter order configurable

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This commit is contained in:
Robert Jördens 2021-10-27 20:24:58 +00:00
parent 3f6bf33298
commit 10c37b87ec
1 changed files with 9 additions and 9 deletions
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18
artiq/coredevice/fastino.py
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@ -39,13 +39,15 @@ class Fastino:
:param core_device: Core device name (default: "core")
:param log2_width: Width of DAC channel group (logarithm base 2).
Value must match the corresponding value in the RTIO PHY (gateware).
:param order: CIC filter interpolation order.
"""
kernel_invariants = {"core", "channel", "width"}
kernel_invariants = {"core", "channel", "width", "order"}
def __init__(self, dmgr, channel, core_device="core", log2_width=0):
def __init__(self, dmgr, channel, core_device="core", log2_width=0, order=3):
self.channel = channel << 8
self.core = dmgr.get(core_device)
self.width = 1 << log2_width
self.order = order
@kernel
def init(self):
@ -222,8 +224,7 @@ class Fastino:
Returns the actual interpolation rate.
The actual overall interpolation gain including gain compensation is
`actual_rate**order/2**ceil(log2(actual_rate**order))`
where `order = 3`.
`actual_rate**order/2**ceil(log2(actual_rate**order))`.
"""
if rate <= 0 or rate > 1 << 16:
raise ValueError("rate out of bounds")
@ -232,15 +233,14 @@ class Fastino:
while rate_mantissa > 1 << 6:
rate_exponent += 1
rate_mantissa >>= 1
order = 3
gain = 1
for i in range(order):
for i in range(self.order):
gain *= rate_mantissa
gain_exponent = 0
while gain > 1 << gain_exponent:
gain_exponent += 1
gain_exponent += order*rate_exponent
assert gain_exponent <= order*16
gain_exponent += self.order*rate_exponent
assert gain_exponent <= self.order*16
self.stage_cic_mu(rate_mantissa - 1, rate_exponent, gain_exponent)
return rate_mantissa << rate_exponent
@ -252,6 +252,6 @@ class Fastino:
continous DAC updates enabled (see :meth:`set_continuous`).
This resets and settles the interpolators. There will be no output
updates for the next `order = 3` input samples.
updates for the next `order` input samples.
"""
self.write(0x27, channel_mask)