XEP MATLAB Connector Notes

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The XEP Radar Connector is an interface which allows MATLAB to interact with the X4 UWB radar remotely. From the Matlab perspective, outside of the initial setup, the functionality of this connector should act identical compared to the SensorLogic Linux XEP MATLAB Connector.

In the current version, streaming radar data is not supported. The vcom_xep_radar_connector connector supports a design where the user will request (poll) for data, and the particular server running will then produce a response message.

Firmware Update

The SLMX4 Firmware can be updated using the Insecure Firmware Update Guide.

vcom_xep_radar_connector

The vcom_xep_radar_connector works on the SLMX4 hardware over USB; this NXP MIMXRT1062 micro-controller platform exposes USB as a virtual COM port.

On Windows, the device will show up in the ‘Device Manager’ under the ‘Ports (COM & LPT)’ category, with the label ‘Virtual Com Port’. The driver should automatically install and have an manufacturer id of ‘NXP’.

Minimal example on capturing a single radar frame:

r = vcom_xep_radar_connector('COM106');
r.Open('X4');

plot(r.GetFrameRawDouble);
r.Close();

Variables

For compatibility with existing scripts, there are two ways to access variable names. Many of the older CamelCase variables are still present, but there are now snake_case equivalents, along with some new ones unique to the XEP driver.

Old Name	Updated Name	Description	Notes
DACMin	dac_min	minimum value of DAC sweep	always set >= 0 and < dac_max
DACMax	dac_max	maximum value of DAC sweep	always set <= 2047 and > dac_min
DACStep	dac_step	step size of DAC sweep	step size exponent, 2^n, n = (0,1,2,or 3)
PPS	pps	number of pulses integrated per DAC step
Iterations	iterations	number of sweep iterations to perform
PRF	prf_div	pulse repetition frequency in Hertz	* fex4’s PRF set is same as prf_div
	prf	pulse repetition frequency in Hertz
SamplingRate	fs	sampling rate in Hertz (23.328 GHz)
SamplersPerFrame	num_samples	number of samples per frame
	frame_length	frame length in steps of 96 sampling bins
RxWait	rx_wait	sets delay for frame_offset
	tx_region	radar center frequency, Tx3 = 7.29 GHz, Tx4 = 8.748 GHz
	tx_power	tx power level (0 = off, 1 = low, 2 = med, 3 = high)
DownConvert	ddc_en	digital down conversion enable for IQ data
	frame_offset	frame offset position in meters according to rx_wait
	frame_start	frame start position in meters
	frame_end	frame end position in meters
	unambiguous_range	unambiguous range in meters based on PRF
	ur	unambiguous range in meters based on PRF	same as unambiguous_range
	sweep_time	calculated time need to a collect radar frame	varies based on sweep settings and PRF

• fex4 is legacy x4 driver not in current use

Provided Scripts

VCOM Test

There is an included script called vcom_test.m. This provides a simple plot window of normalized radar data from the module.

Unit Test

There is an included script called unit_test.m. This is a test of the get and set functions for various adjustable radar settings.

It takes a minute or so to run. The output should look something like:

XEP set/get unit test
---------------------
dac_min test ok? 1
dac_max test ok? 1
dac_step test ok? 1
iterations test ok? 1
pps test ok? 1
prf_div test ok? 1
frame_length test ok? 1
rx_wait test ok? 1
tx_region test ok? 1
tx_power test ok? 1
ddc_en test ok? 1

Timer Test

There is an included script called timer_test.m. This demonstrates how to use a Matlab timer to poll the radar at a governed framerate.

When the script is run, radar data is collected for 10 seconds. After 10 seconds, the radar data is plotted where the x-axis represents the collection of radar frames, and the y-axis represents each radar frame. Distance increases downward along the y-axis, and the color intensity represents signal amplitude.

In the example run, a metal plate was waved towards and away from the radar throughout.