EasyRadar Sensor Evaluation Kit
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•
RFE_Config:
o
Base frequency of the frontend [uint19]. This frequency should be within the ISM band.
o
VCO divider value [uint13]: ratio of RF frequency to divider output
•
PLL_Freq:
o
Ramp bandwidth in MHz as RF frequency [int16], can be positive or negative.
•
BB_Setup:
o
F_Smp [uint3]: ADC sample frequency selection. F_Smp * #Smp = ramp time
o
#Samples [3 bits as 32 + 2
n
]: number of samples per ramp
o
#Ramps [3 bits as 2
n
]: number of ramps to integrate before FFT is calculated
o
Downsample [uint3]: number of downsampling steps before FFT is calculated
o
FFT Size [3 bits as 32 + 2
n
]: Size of FFT in points
o
CFAR guard interval [uint2]: number of guard cells around cell under test
o
CFAR size [uint4]: number of cells to integrate for CFAR operator
o
Threshold [uint5]: target threshold value for CFAR operator in dB
o
Format [uint3]: output format for the target / sample data
•
Programming Mode: t.b.d.; intended use is to enter programming mode from software
8.3.1 Communication from sensor module to backend
Depending on the activated output frames the module can output the following data fields:
•
Range Frame and CFAR Frame: both are activated by the R/C bit in the RFE_CONFIG register. The
range spectrum is returned as magnitude in dB for the target data and the CFAR operator threshold.
•
Target List Frame: activated by the TL bit in RFE_CONFIG. The target list is returned consisting of the
o
selected format,
o
the baseband amp gain used for the last measurement,
o
the target number,
o
the distance,
o
the magnitude in dB,
o
the phase angle phi and
o
the velocity (delta distance since last measurement) for each target.
•
Status Frame: returns the current measurement parameters. This frame is returned every time the
configuration is changed, or after every measurement.
o
Selected format
o
baseband amp gain used for the last measurement,
o
accuracy in mm x 10
o
current maximum range (dependent on FFT size and number of samples/downsampling)
o
current ramp time in µs
o
current bandwidth in MHz
o
time since last measurement as overflowing 16-Bit counter. Max. is 164 ms. Timebase is
400kHz. This value is only available if sleep mode is disabled.
•
Error frame: This frame is returned after every measurement or setup frame that sets at least one of
the error bits.
o
CRC error flag: is asserted when a CRC error in the setup data is detected.
o
RFE setup error flag: is asserted when RFE setup data is out of range (max / min frequency
hit)
o
PLL setup error flag: is asserted when PLL setup data is out of range
o
BB setup error flag: is asserted when baseband setup was wrong (saturation at lowest
gain,..)
o
PRC error flag: is set high when a processing error occurred (FFT_size, ..)
