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sampler: remove v_ref parameter (#988)

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hartytp 2018-05-13 17:00:57 +01:00 committed by Robert Jördens
parent 3027951dd8
commit 00cb31b804
1 changed files with 6 additions and 7 deletions
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13
artiq/coredevice/sampler.py
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@ -16,17 +16,17 @@ SPI_CS_PGIA = 1 # separate SPI bus, CS used as RCLK
@portable
def adc_mu_to_volt(data, gain=0, v_ref=5.):
def adc_mu_to_volt(data, gain=0):
"""Convert ADC data in machine units to Volts.
:param data: 16 bit signed ADC word
:param gain: PGIA gain setting (0: 1, ..., 3: 1000)
:param v_ref: Reference voltage in Volts
:return: Voltage in Volts
"""
input_span = 20.
for i in range(gain):
v_ref /= 10.
volt_per_lsb = v_ref/(1 << 15)
input_span /= 10.
volt_per_lsb = input_span/(1 << 16)
return data*volt_per_lsb
@ -42,7 +42,7 @@ class Sampler:
:param div: SPI clock divider (default: 8)
:param core_device: Core device name
"""
kernel_invariants = {"bus_adc", "bus_pgia", "core", "cnv", "div", "v_ref"}
kernel_invariants = {"bus_adc", "bus_pgia", "core", "cnv", "div"}
def __init__(self, dmgr, spi_adc_device, spi_pgia_device, cnv_device,
div=8, core_device="core"):
@ -52,7 +52,6 @@ class Sampler:
self.cnv = dmgr.get(cnv_device)
self.div = div
self.gains = 0x0000
self.v_ref = 10. # 5 Volt reference, 0.5 AFE diff gain
@kernel
def init(self):
@ -135,4 +134,4 @@ class Sampler:
for i in range(n):
channel = i + 8 - len(data)
gain = (self.gains >> (channel*2)) & 0b11
data[i] = adc_mu_to_volt(adc_data[i], gain, self.v_ref)
data[i] = adc_mu_to_volt(adc_data[i], gain)