iio_readdev(1)

NAME
iio_readdev - read buffers from an IIO device

SYNOPSIS
iio_readdev [ options ] [-n <hostname>] [-t <trigger>] [-T <timeout-ms>] [-b <buffer-size>] [-s <samples>] <iio_device> [<channel> ...]

DESCRIPTION
iio_reg is a utility for reading buffers from connected IIO devices, and sending resutls to standard out.

OPTIONS

-h, --help
    Tells iio_readdev to display some help, and then quit.

-V, --version
    Prints the version information for this particular copy of iio_readdev and the version of the libiio library it is using. This is useful for knowing if the version of the library and iio_readdev on your system are up to date. This is also useful when reporting bugs.

-S, --scan [backends]
    Scan for available IIO contexts, optional arg of specific backend(s) 'ip', 'usb' or 'ip:usb'. Specific options for USB include Vendor ID, Product ID to limit scanning to specific devices 'usb=0456,b673'. vid,pid are hexadecimal numbers (no prefix needed), "*" (match any for pid only) If no argument is given, it checks all that are available.

-t --trigger
    Use the specified trigger, if needed on the specified channel

-b --buffer-size
    Size of the capture buffer. Default is 256.

-s --samples
    Number of samples (not bytes) to capture, 0 = infinite. Default is 0.

-T --timeout
    Buffer timeout in milliseconds. 0 = no timeout. Default is 0.

-u, --uri
    The Uniform Resource Identifier (uri) for connecting to devices, can be one of:

    ip:[address]
        network address, either numeric (192.168.0.1) or network hostname

    ip: blank, if compiled with zeroconf support, will find an IIO device on network

    usb:[device:port:instance]
        normally returned from iio_readdev -S

    serial:[port],[baud],[settings]
        which are controlled, and need to match the iiod (or tinyiiod) on the other end of the serial port.

        [port]
            is something like '/dev/ttyUSB0' on Linux, and 'COM4' on Windows.

        [baud]
            is is normally one of 110, 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 38400, 57600, 115200 [default], 128000 or 256000, but can vary system to system.

        [settings]
            would normally be configured as '8n1' this is controlled by:

            data_bits:
                (5, 6, 7, 8 [default], or 9)

            parity_bits:
                ('n' none [default], 'o' odd, 'e' even, 'm' mark, or 's' space)

            stop_bits:
                (1 [default, or 2)

            flow_control:
                ('0' none [default], 'x' Xon Xoff, 'r' RTSCTS, or 'd' DTRDSR)

    local:
        with no address part.

RETURN VALUE
If the specified device is not found, a non-zero exit code is returned.

USAGE

You use iio_readdev in the same way you use many of the other libiio utilities. You should specify a IIO device, and the specific channel to read. Since this is a read, channels must be input. If no channel is provided, iio_readdev will read from all input channels. If no device is provided, iio_readdev will print a few examples:
    iio_readdev -a
    Using auto-detected IIO context at URI "usb:3.10.5"
    Example : iio_readdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage0
    Example : iio_readdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage1
    Example : iio_readdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage2
    Example : iio_readdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage3
    Example : iio_readdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc

This captures 1024 samples of I and Q data from the USB attached AD9361, and stores it (as raw binary) into the file samples.dat
    iio_readdev -a -s 1024 cf-ad9361-lpc voltage0 voltage1 > samples.dat

And plots the data with gnuplot.
    gnuplot -e "set term png; set output 'sample.png'; plot 'sample.dat' binary format='%short%short' using 1 with lines, 'sample.dat' binary format='%short%short' using 2 with lines;"

SEE ALSO
iio_attr(1), iio_info(1), iio_readdev(1), iio_reg(1), iio_writedev(1), libiio(3)

libiio home page: https://wiki.analog.com/resources/tools-software/linux-software/libiio

libiio code: https://github.com/analogdevicesinc/libiio

Doxygen for libiio https://analogdevicesinc.github.io/libiio/

BUGS
All bugs are tracked at: https://github.com/analogdevicesinc/libiio/issues