USRP Hardware Driver and USRP Manual: USRP B2x0
Series
Comparative features list - B200/B210/B200mini
Hardware Capabilities:
Integrated RF frontend (70 MHz - 6 GHz)
External PPS reference input
External 10 MHz reference input
Configurable clock rate
Variable analog bandwidth (200 kHz - 56 MHz)
GPIO header
[B200/B210] Internal GPSDO option (see Internal GPSDO Application
Notes (USRP-B2x0 Models) for details)
[B210/B200mini] JTAG Connector
[B210] MICTOR Debug Connector
FPGA Capabilities:
Timed commands in FPGA
Timed sampling in FPGA
Power
In most cases, USB 3.0 bus power will be sufficient to power the device. If using USB
2.0 or a GPSDO, an external power supply or a cable designed to pull power from 2 USB
ports (USB 3.0 dual A to micro-B or B) must be used.
Specifying a Non-standard Image
UHD software will automatically select the USRP B2X0 images from the installed
images package. The image selection can be overridden with the fpga and fw device
address parameters.
Example device address string representations to specify non-standard images:
fpga=usrp_b200_fpga.bin
-- OR --
fw=usrp_b200_fw.hex
Custom FPGA images and accessing user settings
The FPGA image is provided in source code and can thus be modified and rebuilt to
serve custom purposes. For example, additional filtering or other DSP operations can
be inserted into the FPGA before or after the DAC or ADC stages, respectively. Refer to
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the FPGA Manual for further information on how to rebuild the FPGA.
To control user-defined IP, the USER_SETTINGS parameter for the radio_legacy block
in b200_core.v (for B210 and B200) or b205_core.v (for the mini series) need to be
set to 1, and radio_legacy.v can then be modified to include user-defined read and write
registers (the file includes examples on how to do that). Any customizations will most
likely also be applied in radio_legacy.v.
For FPGA images that include user settings registers, UHD provides APIs to interface
with those. To enable access to user settings, apply the enable_user_regs device
argument on initialization. Then, use the uhd::multi_usrp::get_user_settings_iface API
call to access an object that allows modifying the registers. Example:
auto usrp = multi_usrp::make("type=b200,enable_user_regs");
auto user_regs = usrp->get_user_settings_iface();
user_regs->poke32(addr, data);
Changing the Master Clock Rate
The master clock rate feeds the RF frontends and the DSP chains. Users may select nondefault clock rates to achieve integer decimation rates or interpolations in the DSP
chains. The clock rate can be set to any value between 5 MHz and 61.44 MHz (or 30.72
MHz for dual-channel mode). Note that rates above 56 MHz are possible, but not
recommended.
The user can set the master clock rate through the usrp API call
uhd::usrp::multi_usrp::set_master_clock_rate(), or the clock rate can be set through
the device arguments, which many applications take:
uhd_usrp_probe --args="master_clock_rate=52e6"
The property to control the master clock rate is a double value, called tick_rate .
Automatic Clock Rate Setting
The default clock rate setting is to automatically set a clock rate depending on the
requested sampling rate. The automatic clock rate selection is disabled when either
master_clock_rate is given in the device initialization arguments, or when
uhd::usrp::multi_usrp::set_master_clock_rate() is called.
Note that the master clock rate must be an integer multiple of the sampling rate. If a
master clock rate is chosen for which this condition does not hold, a warning will be
displayed and a different sampling rate is used internally.
Nevertheless, there are multiple valid values for the master clock rate for most sampling
rates. The auto clock rate selection attempts to use the largest possible clock rate as to
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enable as many half-band filters as possible. Expert users might have cases where a
more fine-grained control over the resampling stages is required, in which case
manually selecting a master clock rate might be more suitable than the automatic rate.
The property to dis- or enable the auto tick rate is a boolean value, auto_tick_rate .
RF Frontend Notes
The B200 features an integrated RF frontend.
Frontend tuning
The RF frontend has individually tunable receive and transmit chains. On the B200 and
B200 mini, there is one transmit and one receive RF frontend. On the B210, both
transmit and receive can be used in a MIMO configuration. For the MIMO case, both
receive frontends share the RX LO, and both transmit frontends share the TX LO. Each
LO is tunable between 50 MHz and 6 GHz.
Frontend gain
All frontends have individual analog gain controls. The receive frontends have 76 dB of
available gain; and the transmit frontends have 89.8 dB of available gain. Gain settings
are application specific, but it is recommended that users consider using at least half of
the available gain to get reasonable dynamic range.
Frontend bandwidth
The analog frontend has a seamlessly adjustable bandwidth of 200 kHz to 56 MHz.
Generally, when requesting any possible master clock rate, UHD will automatically
configure the analog filters to avoid any aliasing (RX) or out-of-band emissions whilst
letting through the cleanest possible signal.
If you, however, happen to have a very strong interferer within half the master clock
rate of your RX LO frequency, you might want to reduce this analog bandwidth. You
can do so by calling uhd::usrp::multi_usrp::set_rx_bandwidth(bw).
The property to control the analog RX bandwidth is bandwidth/value .
UHD will not allow you to set bandwidths larger than your current master clock rate.
Power API
The B200 series support the UHD power calibration API (see: Power Level Controls).
The TX path and the two RX paths have their own calibration data, resulting in 6 sets of
calibration data total for the B210, and 3 for all the others.
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Devices have to be manually calibrated using a calibrated power meter or signal
generator.
Hardware Reference
LED Indicators
Below is a table of the B200/B210 LED indicators and their meanings:
Component
ID Description Details
LED600 Power
Indicator
off = no power applied (before rev6, some rev6) /
external power applied and not yet initialized (most
rev6)
blue = USB power applied (before rev6) / power
supplied (USB) OR power supplied (external) (rev6)
red = external power applied (before rev6) / external
power applied and device initialized (rev6)
LED800 Channel 2
RX2 Activity
off = no power applied
green = receiving
LED801 Channel 2
TX/RX
Activity
off = no activity
green = receiving
red = transmitting
orange = switching between transmitting and receiving
LED802 Channel 1
TX/RX
Activity
off = no activity
green = receiving
red = transmitting
orange = switching between transmitting and receiving
LED803 Channel 1
RX2 Activity
off = no power applied
green = receiving
LED100 GPS lock
indicator
off = no lock
green = lock
Below is a table of the B200mini LED indicators and their meanings:
Component
ID Description Details
PWR LED Power Indicator off = no power applied
on = power applied (external or USB)
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TRX LED TX/RX Activity off = no activity
green = receiving
red = transmitting
orange = switching between transmitting and
receiving
RX2 LED RX2 Activity off = no activity
green = receiving
S0 LED Reference Lock off = no activity
green = locked
S1 LED Reference
Present
off = reference level low or not present
green = reference level high
TX LED indicators are on when transmitting data and off when no samples are available
to transmit. RX LED indicators are on when sending samples to the host and off when
unable to do so. This means that TX/RX activity LED indicators will blink off in a
temporary transmit underflow or receive overflow condition, indicating that the host is
not sending or receiving samples fast enough. The host will be notified of the condition
and output a "U" or "O" as well.
External Connections
Below is a table showing the B200/B210 external connections and respective power
information:
Component
ID Description Details
J601 External Power 6 V
3 A
J701 USB Connector USB 3.0
J104 External PPS Input 1.8 V - 5 V
J101 GPS Antenna GPSDO will supply nominal voltage to
antenna.
J100 External 10 MHz
Input
+15 dBm max
J800 RF B: TX/RX TX power +20 dBm max
RX power -15 dBm max
J802 RF B: RX2 RX power -15 dBm max
J803 RF A: RX2 RX power -15 dBm max
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J801 RF A: TX/RX TX power +20 dBm max
RX power -15 dBm max
Below is a table showing the B200mini external connections and respective power
information:
Component ID Description Details
USB3 USB Connector USB 3.0
J1 TRX TX power +20 dBm
max
RX power -15 dBm max
J2 RX2 RX power -15 dBm max
J3 External 10 MHz/PPS
Reference
+15 dBm max
On-Board Connectors and Switches
Below is a table showing the B200/B210 on-board connectors and switches:
Component
ID Description Details
J502 Mictor Connector Interface to FPGA for I/O and inspection.
J503 JTAG Header Interface to FPGA for programming and
debugging.
J504 GPIO Header Header connected to the FPGA for GPIO
purposes.
S700 FX3 Hard Reset
Switch
Resets the USB controller / System reset
U100 GPSDO socket Interface to GPS disciplined reference
oscillator
Only on the B210
Only since rev. 6 (green board). GPIO pinout is 1=GPIO_0, 2=GPIO_1, 3=GPIO_2,
4=GPIO_3, 5=GPIO_4, 6=GPIO_5, 7=GPIO_6, 8=GPIO_7, 9=GND, 10=GND
Below is a table showing the B200mini on-board connectors and switches:
Component
ID Description Details
1
1
2
1
2
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J5 JTAG Header Interface to FPGA for programming and
debugging.
J6 GPIO Header Header connected to the FPGA for GPIO
purposes.
SW1 FX3 Hard Reset
Switch
Resets the USB controller / System reset
GPIO pinout is 1=3.3V, 2=GPIO_0, 3=GPIO_1, 4=GPIO_2, 5=GPIO_3, 6=GND,
7=3.3V, 8=GPIO_4, 9=GPIO_5, 10=GPIO_6, 11=GPIO_7, 12=GND
Known issues
The B200 and B210 cannot support an external 10 MHz reference if a GPSDO is
already present on the motherboard. If an external 10 MHz reference is to be used,
the GPSDO needs to be physically removed from the device beforehand.
The default streaming settings do not work optimally for all use cases. If there are
issues with performance or stability, it can help to modify the recv_frame_size
values, e.g., by setting recv_frame_size=1024 as part of the device args.
USRP Hardware Driver and USRP Manual Version:
4.0.0.0-30-g67651b9ff
UHD and USRP Manual
1
1
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