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iio_rwdev

Section: LibIIO Utilities (1)
Updated: 30 April 2026
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NAME

iio_rwdev - read/write buffers from/to an IIO device  

SYNOPSIS

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

DESCRIPTION

iio_rwdev is a utility for reading buffers from connected IIO devices, and sending results to standard out.

 

OPTIONS

-h, --help
Tells iio_rwdev to display some help, and then quit.
-V, --version
Prints the version information for this particular copy of iio_rwdev and the version of the libiio library it is using. This is useful for knowing if the version of the library and iio_rwdev 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.
-w --write
Write sample data to the IIO device. The default is to read samples from it.
-t --trigger <arg>
Use the specified trigger, if needed on the specified channel
-r --trigger-rate <arg>
Set the trigger to the specified rate (Hz). Default is 100 Hz.
-b --buffer-size <arg>
Size of the capture buffer. Default is 256.
-s --samples <arg>
Number of samples (not bytes) to capture, 0 = infinite. Default is 0.
-c --cyclic
Use cyclic buffer mode.
-B --benchmark
Benchmark throughput. Statistics will be printed on the standard input.
-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_rwdev -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.
-T, --timeout <arg>
Context timeout in milliseconds. 0 = no timeout (wait forever). Default is 0.
 

RETURN VALUE

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

 

USAGE

You use iio_rwdev in the same way you use many of the other libiio utilities. You should specify a IIO device, and the specific channel to read or write. When reading, channels must be input; when writing they must be output. If no channel is provided, iio_rwdev will read from all input channels or write to all output channels. If no device is provided, iio_rwdev will print a few examples:

iio_rwdev -a
Using auto-detected IIO context at URI "usb:3.10.5"
Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage0
Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage1
Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage2
Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage3
Example : iio_rwdev -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_rwdev -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_rwdev(1), iio_reg(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

 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
RETURN VALUE
USAGE
SEE ALSO
BUGS
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Time: 05:46:30 GMT, April 30, 2026