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====== AD9832 IIO Direct Digital Synthesis Linux Driver ======

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

  * [[adi>AD9832]]
  * [[adi>AD9835]]


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

  * [[adi>EVAL-AD9832SDZ]]
===== 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/ad9832.c|git]] |[[git.linux.org>drivers/staging/iio/frequency/ad9832.c|Yes]] |
===== Files =====

^ Function ^ File ^
| driver  | [[git.linux.org>drivers/staging/iio/frequency/ad9832.c]] |
| include | [[git.linux.org>drivers/staging/iio/frequency/ad9832.h]] |

====== Example platform device initialization ======

{{page>software/linux/docs/platform_and_bus_model#Platform Data&noheader&firstseconly&noeditbtn}}

The reference voltage may vary between boards and models. The platform_data for the device's "struct device" holds this information.

<source trunk/drivers/staging/iio/dds/ad9832.h:ad9832_platform_data{} c linux-kernel>

<code c>
/**
 * struct ad9832_platform_data - platform specific information
 * @mclk:		master clock in Hz
 * @freq0:		power up freq0 tuning word in Hz
 * @freq1:		power up freq1 tuning word in Hz
 * @phase0:		power up phase0 value [0..4095] correlates with 0..2PI
 * @phase1:		power up phase1 value [0..4095] correlates with 0..2PI
 * @phase2:		power up phase2 value [0..4095] correlates with 0..2PI
 * @phase3:		power up phase3 value [0..4095] correlates with 0..2PI
 */

struct ad9832_platform_data ad9832_pdata = {
	.mclk = 25000000,
	.freq0 = 1000000,
	.freq1 = 2000000,
	.phase0 = 512,
	.phase1 = 1024,
	.phase0 = 2048,
	.phase1 = 0,

};
</code>

{{page>software/linux/docs/platform_and_bus_model#Declaring SPI slave devices&firstseconly&noeditbtn}}

Depending on the DDS IC used, you may need to set the modalias accordingly, matching your part name.
It may also required to adjust max_speed_hz. Please consult the datasheet, for maximum spi clock supported by the device in question.

<code c>
static struct spi_board_info board_spi_board_info[] __initdata = {
#if defined(CONFIG_AD9832) \
	|| defined(CONFIG_AD9832_MODULE)
	{
		.modalias = "ad9832",
		.max_speed_hz = 1000000,     /* max spi clock (SCK) speed in HZ */
		.bus_num = 0,
		.chip_select = 3, /* CS, change it for your board */
		.platform_data = &ad9832_pdata, /* No spi_driver specific config */
		.mode = SPI_MODE_2,
	},
#endif
};
</code>

<code c>
static int __init board_init(void)
{
	[--snip--]

	spi_register_board_info(board_spi_board_info, ARRAY_SIZE(board_spi_board_info));

	[--snip--]

	return 0;
}
arch_initcall(board_init);
</code>

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

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

<WRAP round help>
The AD9832 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 ad9832/5 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 15:11 dds0_freq0
--w-------    1 root     root          4096 Jan  3 15:11 dds0_freq1
-r--r--r--    1 root     root          4096 Jan  3 15:11 dds0_freq_scale
--w-------    1 root     root          4096 Jan  3 15:11 dds0_freqsymbol
--w-------    1 root     root          4096 Jan  3 15:11 dds0_out_enable
--w-------    1 root     root          4096 Jan  3 15:11 dds0_phase0
--w-------    1 root     root          4096 Jan  3 15:11 dds0_phase1
--w-------    1 root     root          4096 Jan  3 15:11 dds0_phase2
--w-------    1 root     root          4096 Jan  3 15:11 dds0_phase3
-r--r--r--    1 root     root          4096 Jan  3 15:11 dds0_phase_scale
--w-------    1 root     root          4096 Jan  3 15:11 dds0_phasesymbol
--w-------    1 root     root          4096 Jan  3 15:11 dds0_pincontrol_en
-r--r--r--    1 root     root          4096 Jan  3 15:11 name
drwxr-xr-x    2 root     root             0 Jan  3 15:11 power
lrwxrwxrwx    1 root     root             0 Jan  3 15:11 subsystem -> ../../../../../bus/iio
-rw-r--r--    1 root     root          4096 Jan  3 15:11 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**
ad9832
</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_freq1**
</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..3 ===

/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 0 > dds0_phase0**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 512 > dds0_phase1**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 1024 > dds0_phase2**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 2048 > dds0_phase3**
</xterm></WRAP>

**phase0** = //dds0_phase0 * ddsX_phaseY_scale// = 0 * 0.0015339808 = **0 rad**\\
**phase1** = //dds0_phase1 * ddsX_phaseY_scale// = 512 * 0.0015339808 = PI/4 = **0.7853981696 rad**\\
**phase0** = //dds0_phase2 * ddsX_phaseY_scale// = 1024 * 0.0015339808 = PI/2 = **1.5707963 rad**\\
**phase1** = //dds0_phase3 * ddsX_phaseY_scale// = 2048 * 0.0015339808 = PI = **3.1415926 rad**

=== 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**
</xterm></WRAP>

=== Switch between phase symbol 0..3 ===

/sys/bus/iio/devices/.../ddsX_phasesymbol\\

Specifies the active phase Y which is added to the phase
accumulator output. The value corresponds to the Y in
ddsX_phaseY. To exit this mode the user can write
ddsX_pincontrol_phase_en or disable 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 0 > dds0_phasesymbol**
root:/sys/devices/platform/bfin-spi.0/spi0.3/device0> **echo 1 > dds0_phasesymbol**
</xterm></WRAP>

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

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