/*! \page page_usrp_e1x0 USRP-E1x0 Series

\tableofcontents

\section e1x0_features Comparative features list

- Hardware Capabilities:
    -   1 transceiver card slot
    -   Internal PPS reference input
    -   Internal 10 MHz reference input
    -   Configurable clock rate (defaults to 64 MHz)
    -   Internal GPSDO option
- FPGA Capabilities:
    -   2 RX DDC chains in FPGA
    -   1 TX DUC chain in FPGA
    -   Timed commands in FPGA
    -   Timed sampling in FPGA
    -   sc8 and sc16 sample modes
        -   Up to 8 MHz of RF BW with 16-bit samples
        -   Up to 16 MHz of RF BW with 8-bit samples

\section e1x0_imgs Specify a Non-standard Image

UHD software will automatically select the USRP-Embedded FPGA image from
the installed images package. The FPGA image selection can be overridden
with the `fpga` device address parameter.

Example device address string representations to specify non-standard
FPGA image:

    fpga=usrp_e100_custom.bin

\section e1x0_mcr Changing the Master Clock Rate

The master clock rate of the USRP-Embedded feeds both the FPGA DSP and
the codec chip. Hundreds of rates between 32 MHz and 64 MHz are
available. A few notable rates are:

-   **64 MHz:** maximum rate of the codec chip
-   **61.44 MHz:** good for UMTS/WCDMA applications
-   **52 MHz:** good for GSM applications

\subsection e1x0_mcr_extvcxo Set 61.44MHz - uses external VCXO

To use the 61.44 MHz clock rate with the USRP-Embedded, two jumpers must
be moved on the device.

-   **J16** is a two pin header; remove the jumper (or leave it on pin1
    only).
-   **J15** is a three pin header; move the jumper to (pin1, pin2).

**Note:** See instructions below to communicate the desired clock rate
to UHD software.

\subsection e1x0_intvco Set other rates - uses internal VCO

To use other clock rates, the jumpers will need to be in the default
position.

-   **J16** is a two pin header; move the jumper to (pin1, pin2).
-   **J15** is a three pin header; move the jumper to (pin2, pin3).

To communicate the desired clock rate into UHD software, specify the a
special device address argument, where the key is
`master_clock_rate` and the value is a rate in Hz. Example:

    uhd_usrp_probe --args="master_clock_rate=52e6"

\section e1x0_clksync Clock Synchronization

\subsection e1x0_clksync_ref Ref Clock - 10MHz

The E1xx has a 10MHz TCXO which can be used to discipline the flexible
clocking by selecting `REF_INT` for the uhd::clock_config_t.

Alternately, an external 10MHz reference clock can be supplied by
soldering a connector.

-   Connector **J10** (REF_IN) needs MCX connector **WM5541-ND** or
    similar.
-   Square wave will offer the best phase noise performance, but
    sinusoid is acceptable.
-   **Power level:** 0 to 15dBm
-   Select `REF_SMA` in uhd::clock_config_t.

\subsection e1x0_clksync_pps PPS - Pulse Per Second

An external PPS signal for timestamp synchronization can be supplied by
soldering a connector.

-   Connector **J13** (PPS) needs MCX connector **WM5541-ND** or
    similar.
-   Requires a square wave signal.
-   **Amplitude:** 3.3 to 5 Vpp

Test the PPS input with the following app (`<args>` are device
address arguments, optional if only one USRP device is on your machine):

    cd <install-path>/lib/uhd/examples
    ./test_pps_input --args=<args>

\subsection e1x0_clksync_gpsdo Internal GPSDO

Please see the \subpage page_gpsdo for
information on configuring and using the internal GPSDO.

UHD software will always try to detect an installed GPSDO at runtime. It
is not necessary to burn a special EEPROM value for GPSDO detection.

\section e1x0_hw Hardware Setup Notes

\subsection e1x0_hw_leds Front panel LEDs

The LEDs on the front panel can be useful in debugging hardware and
software issues. The LEDs reveal the following about the state of the
device:

-   **LED A:** transmitting
-   **LED B:** PPS signal
-   **LED C:** receiving
-   **LED D:** FPGA loaded
-   **LED E:** reference lock
-   **LED F:** board power

\section e1x0_misc Miscellaneous

\subsection e1x0_misc_sensors Available Sensors

The following sensors are available; they can be queried through the
API.

-   **ref_locked:** clock reference locked (internal/external)
-   other sensors are added when the GPSDO is enabled

*/
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