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====== AD9834 IIO Direct Digital Synthesis Linux Driver ======

===== Supported Devices =====

  * [[adi>AD9833]]
  * [[adi>AD9834]]
  * [[adi>AD9837]]
  * [[adi>AD9838]]


===== Reference Circuits =====

  * [[adi>CN0156]]

===== Evaluation Boards =====

  * [[adi>EVAL-AD9833SDZ]]
  * [[adi>EVAL-AD9834SDZ]]
  * [[adi>EVAL-AD9837SDZ]]
  * [[adi>EVAL-AD9838SDZ]]
===== Description =====

This is a Linux industrial I/O ([[software:linux:docs:iio:iio|IIO]]) subsystem driver, targeting serial interface DDS controllers.
The industrial I/O subsystem provides a unified framework for drivers for many different types of converters and sensors using a number of different physical interfaces (i2c, spi, etc).
See [[software:linux:docs:iio:iio|IIO]] for more information.

====== Source Code ======

===== Status =====

^ Source ^ Mainlined? ^
| [[git.linux.org>drivers/staging/iio/frequency/ad9834.c|git]] | [[git.linux.org>drivers/staging/iio/frequency/ad9834.c|Yes]] |
===== Files =====

^ Function ^ File ^
| driver  | [[git.linux.org>drivers/staging/iio/frequency/ad9834.c]] |
| include | [[git.linux.org>drivers/staging/iio/frequency/ad9834.h]] |

====== Example device-tree ======

In the example below, it's assumed that **spi0** is the SPI controller to which the AD983X is attached to. Typically, these are defined in the board device-tree where the AD983X is attached to.

<code c>

	&spi0 {
		#address-cells = <1>;
		#size-cells = <0>;
		status = "okay";

		ad9833@0{
			#clock-cells = <0>;
			compatible = "adi,ad9833";
			reg = <0>;
			spi-max-frequency = <1000000>;
			spi-cpol;
			clocks = <&osc>;
			vcc-supply = <&vcc>;
		};
	};
</code>

This example also references a regulator (vcc-supply) and a clock (osc). These can be left out, in which case it's assumed they are somehow hard-wired on the board to a proper voltage supply and clock source.

The **compabtible** string can be any of the following:
  * adi,ad9833
  * adi,ad9834
  * adi,ad9837
  * adi,ad9838

Note that, the *adi,* prefix can be omitted and this still works. It is preferred to be added to avoid any potential collisions with other drivers from other vendors.

However, the voltage supply & clock can be defined via device-tree as well.
See example below:

<code c>
	/ {
		vcc: fixedregulator@0 {
			compatible = "regulator-fixed";
			regulator-name = "fixed-supply";
			regulator-min-microvolt = <2500000>;
			regulator-max-microvolt = <2500000>;
			regulator-boot-on;
		};

		osc: oscillator {
			#clock-cells = <0>;
			compatible = "fixed-clock";
			clock-frequency = <25000000>;
		};
	};
</code>

This assumes that the board has the chips & drivers to generate voltages like this & clock frequencies.

====== Adding Linux driver support ======

Configure kernel with "make menuconfig" (alternatively use "make xconfig" or
"make qconfig")

<WRAP round help>
The AD9834 Driver depends on **CONFIG_SPI**
</WRAP>

<code>
Linux Kernel Configuration
	Device Drivers  --->
		[*] Staging drivers  --->
			<*>     Industrial I/O support --->
			    --- Industrial I/O support
			    -*-   Enable ring buffer support within IIO
			    -*-     Industrial I/O lock free software ring
			    -*-   Enable triggered sampling support

			          *** Direct Digital Synthesis ***
			    [--snip--]

			    <*>   Analog Devices ad9833/4/ driver

			    [--snip--]

</code>

====== Hardware configuration ======


====== Driver testing ======

{{page>software:linux:docs:iio:iio_snippets#iio device files&noheader&firstseconly&noeditbtn}}

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/> **cd /sys/bus/iio/devices/**
root:/sys/bus/iio/devices> ls
device0
root:/sys/bus/iio/devices> **cd device0**

root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **ls -l**
--w-------    1 root     root          4096 Jan  3 14:06 dds0_freq0
--w-------    1 root     root          4096 Jan  3 14:06 dds0_freq1
-r--r--r--    1 root     root          4096 Jan  3 14:06 dds0_freq_scale
--w-------    1 root     root          4096 Jan  3 14:06 dds0_freqsymbol
--w-------    1 root     root          4096 Jan  3 14:06 dds0_out0_wavetype
-r--r--r--    1 root     root          4096 Jan  3 14:06 dds0_out0_wavetype_available
--w-------    1 root     root          4096 Jan  3 14:06 dds0_out1_enable
--w-------    1 root     root          4096 Jan  3 14:06 dds0_out1_wavetype
-r--r--r--    1 root     root          4096 Jan  3 14:06 dds0_out1_wavetype_available
--w-------    1 root     root          4096 Jan  3 14:06 dds0_out_enable
--w-------    1 root     root          4096 Jan  3 14:06 dds0_phase0
--w-------    1 root     root          4096 Jan  3 14:06 dds0_phase1
-r--r--r--    1 root     root          4096 Jan  3 14:06 dds0_phase_scale
--w-------    1 root     root          4096 Jan  3 14:06 dds0_phasesymbol
--w-------    1 root     root          4096 Jan  3 14:06 dds0_pincontrol_en
-r--r--r--    1 root     root          4096 Jan  3 14:06 name
drwxr-xr-x    2 root     root             0 Jan  3 14:06 power
lrwxrwxrwx    1 root     root             0 Jan  3 14:06 subsystem -> ../../../../../bus/iio
-rw-r--r--    1 root     root          4096 Jan  3 14:06 uevent
</xterm></WRAP>


=== Show device name ===


<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **cat name**
ad9834
</xterm></WRAP>

=== Show frequency scale ===

/sys/bus/iio/devices/.../ddsX_freqY_scale\\

Scale to be applied to ddsX_freqY in order to obtain the
desired value in Hz. If shared across all frequency registers
Y is not present. It is also possible X is not present if
shared across all channels.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **cat dds0_freq_scale**
1
</xterm></WRAP>

=== Set frequency symbol 0/1 ===

/sys/bus/iio/devices/.../ddsX_freqY\\

Stores frequency into tuning word Y.
There will be more than one ddsX_freqY file, which allows for
pin controlled FSK Frequency Shift Keying
(ddsX_pincontrol_freq_en is active) or the user can control
the desired active tuning word by writing Y to the
ddsX_freqsymbol file.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 1000000 > dds0_freq0**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 500000 > dds0_freq0**
</xterm></WRAP>

**freq0** = //ddsX_freq0 * dds0_freq_scale// = 1000000 * 1 = **1 MHz**\\
**freq1** = //ddsX_freq1 * dds0_freq_scale// = 500000 * 1 = **500 kHz**


=== Show phase scale ===

/sys/bus/iio/devices/.../ddsX_phaseY_scale\\

Scale to be applied to ddsX_phaseY in order to obtain the
desired value in rad. If shared across all phase registers
Y is not present. It is also possible X is not present if
shared across all channels.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **cat dds0_phase_scale**
0.0015339808
</xterm></WRAP>

=== Set phase symbol 0/1 ===

/sys/bus/iio/devices/.../ddsX_phaseY\\

Stores phase into Y.
There will be more than one ddsX_phaseY file, which allows for
pin controlled PSK Phase Shift Keying
(ddsX_pincontrol_phase_en is active) or the user can
control the desired phase Y which is added to the phase
accumulator output by writing Y to the en_phase file.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 512 > dds0_phase0**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 2048 > dds0_phase0**
</xterm></WRAP>

**phase0** = //dds0_phase0 * ddsX_phaseY_scale// = 512 * 0.0015339808 = **0.7853981696 rad**\\
**phase1** = //dds0_phase1 * ddsX_phaseY_scale// = 2048 * 0.0015339808 = PI = **3.1415926 rad**
=== List available wavetypes ===

/sys/bus/iio/devices/.../ddsX_outY_wavetype_available\\

Lists all available output waveform options.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **cat dds0_out0_wavetype_available**
sine triangle
</xterm></WRAP>

=== Set wavetype ===

/sys/bus/iio/devices/.../ddsX_outY_wavetype \\

Specifies the output waveform.
(sine, triangle, ramp, square, ...)
For a list of available output waveform options read
available_output_modes.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo sine > dds0_out0_wavetype**
</xterm></WRAP>

=== Disable FSK/PSK pincontrol ===

/sys/bus/iio/devices/.../ddsX_pincontrol_en\\

ddsX_pincontrol_en: Both, the active frequency and phase is
controlled by the respective phase and frequency control inputs.
In case the device in question allows to independent controls,
then there are dedicated files (ddsX_pincontrol_freq_en,
ddsX_pincontrol_phase_en).

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 0 > dds0_pincontrol_en**
</xterm></WRAP>

=== Enable output 0 ===

/sys/bus/iio/devices/.../ddsX_out_enable\\
/sys/bus/iio/devices/.../ddsX_outY_enable\\

ddsX_outY_enable controls signal generation on output Y of
channel X. Y may be suppressed if all channels are
controlled together.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 1 > dds0_out_enable**
</xterm></WRAP>

=== Switch between frequency symbol 0/1 ===

/sys/bus/iio/devices/.../ddsX_freqsymbol\\

Specifies the active output frequency tuning word. The value
corresponds to the Y in ddsX_freqY. To exit this mode the user
can write ddsX_pincontrol_freq_en or ddsX_out_enable file.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 1 > dds0_freqsymbol**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 0 > dds0_freqsymbol**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0>
</xterm></WRAP>


====== More Information ======

{{page>software:linux:docs:iio:iio_snippets#iio pointers&noheader&firstseconly&noeditbtn}}
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