Wiki

Below is the source of this page. To edit this source as well as other pages on the wiki, you must login.
====== AD5933 IIO Impedance Converter and Network Analyzer Linux Driver ======

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

  * [[adi>AD5933]]
  * [[adi>AD5934]]

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

  * [[adi>EVAL-AD5933EBZ]]

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

  * [[adi>CN0217]]
  * [[adi>CN0349]]
===== Description =====

This is a Linux industrial I/O ([[software:linux:docs:iio:iio|IIO]]) subsystem driver, targeting Impedance Converters and Network Analyzers.
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/impedance-analyzer/ad5933.c|git]] | [[git.linux.org>drivers/staging/iio/impedance-analyzer/ad5933.c|Yes]] |

===== Files =====

^ Function ^ File ^
| driver  | [[staging.kernel.org>drivers/staging/iio/impedance-analyzer/ad5933.c]] |

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

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

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

//File//: drivers/staging/iio/impedance-analyzer/ad5933.h:ad5933_platform_data\\

<code c>
/**
 * struct ad5933_platform_data - platform specific data
 * @ext_clk_Hz:		the external clock frequency in Hz, if not set
 *			the driver uses the internal clock (16.776 MHz)
 * @vref_mv:		the external reference voltage in millivolt
 */

struct ad5933_platform_data {
	unsigned long			ext_clk_Hz;
	unsigned short			vref_mv;
};
</code>

<code c>
static struct ad5933_platform_data ad5933_pdata  = {
	.vref_mv = 3300,
};
</code>

<WRAP tip>
In case platform_data is not present or set to NULL, the driver will use the AD5933 internal 16.776MHz reference clock.
</WRAP>

{{page>software/linux/docs/platform_and_bus_model#Declaring I2C devices&firstseconly&noeditbtn}}

Depending on the converter IC used, you may need to set the I2C_BOARD_INFO name accordingly, matching your part name.

^ ADI part number ^ I2C_BOARD_INFO Name ^
| AD5933 | ad5933 |
| AD5934 | ad5934 |


<code c>
static struct i2c_board_info __initdata board_i2c_board_info[] = {
#if defined(CONFIG_AD5933) || defi
ned(CONFIG_AD5933_MODULE)
	{
		I2C_BOARD_INFO("ad5933", 0x0D),
		.platform_data = (void *)&ad5933_pdata, /* optional */
	},
#endif
};
</code>

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

	i2c_register_board_info(0, board_i2c_board_info,
				ARRAY_SIZE(board_i2c_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 driver depends on **CONFIG_I2C**
</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

			    [--snip--]

				*** Network Analyzer, Impedance Converters ***
			    <*>   Analog Devices AD5933, AD5934 driver

			    [--snip--]

</code>

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

{{:resources:tools-software:linux-drivers:iio-impedance-analyzer:ad5933_eval_lr.jpg?600|}}
====== 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
iio:device0
root:/sys/bus/iio/devices> **cd iio:device0**

root:/sys/bus/iio/devices/iio:deviceX> **ls -l**
drwxr-xr-x    4 root     root             0 Jan  1 21:48 buffer
-rw-r--r--    1 root     root          4096 Jan  1 21:48 in_voltage0_scale
-r--r--r--    1 root     root          4096 Jan  1 21:48 in_voltage0_scale_available
-r--r--r--    1 root     root          4096 Jan  1 21:48 name
-rw-r--r--    1 root     root          4096 Jan  1 21:48 out_voltage0_freq_increment
-rw-r--r--    1 root     root          4096 Jan  1 21:48 out_voltage0_freq_points
-rw-r--r--    1 root     root          4096 Jan  1 21:48 out_voltage0_freq_start
-rw-r--r--    1 root     root          4096 Jan  1 21:48 out_voltage0_scale
-r--r--r--    1 root     root          4096 Jan  1 21:48 out_voltage0_scale_available
-rw-r--r--    1 root     root          4096 Jan  1 21:48 out_voltage0_settling_cycles
drwxr-xr-x    2 root     root             0 Jan  1 21:48 power
lrwxrwxrwx    1 root     root             0 Jan  1 21:48 subsystem -> ../../../o
-r--r--r--    1 root     root          4096 Jan  1 21:48 in_temp0_raw
-rw-r--r--    1 root     root          4096 Jan  1 21:48 uevent 
</xterm></WRAP>

=== Show device name ===

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **cat name**
ad5933
</xterm></WRAP>

=== Set sweep start frequency ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/out_voltageY_freq_start\\

Frequency sweep start frequency in Hz.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **echo 15000 > out_voltage0_freq_start**
root:/sys/bus/iio/devices/iio:deviceX> cat out_voltage0_freq_start
14999 
</xterm></WRAP>

=== Set frequency increment ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/out_voltageY_freq_increment\\
Frequency increment in Hz (step size) between consecutive frequency points along the sweep.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **echo 200 > out_voltageY_freq_increment**
</xterm></WRAP>

=== Set number of frequency points ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/out_voltage0_freq_points\\
Number of frequency points (steps) in the frequency sweep.
This value, in conjunction with the out_voltageY_freq_start and the
out_voltageY_freq_increment, determines the frequency sweep range
for the sweep operation.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **echo 100 > out_voltage0_freq_points**
root:/sys/bus/iio/devices/iio:deviceX> cat out_voltage0_freq_points
100
</xterm></WRAP>

=== Set number of settling time cycles ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/out_voltage0_settling_cycles\\
Number of output excitation cycles (settling time cycles)
that are allowed to pass through the unknown impedance,
after each frequency increment, and before the ADC is triggered
to perform a conversion sequence of the response signal.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **echo 15 > out_voltage0_settling_cycles**
root:/sys/bus/iio/devices/iio:deviceX> cat out_voltage0_settling_cycles
15
</xterm></WRAP>

=== Show available output ranges ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/out_voltage0_scale_available\\
List available output scales/ranges in millivolt.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **cat out_voltage0_scale_available**
1980 970 383 198
</xterm></WRAP>

=== Set output range ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/out_voltage0_scale\\
Sets output scale/range in millivolt.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **echo 1980 > out_voltage0_scale**
root:/sys/bus/iio/devices/iio:deviceX> **cat out_voltage0_scale**
1980
</xterm></WRAP>

=== Show available input scales ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/in_voltage0_scale_available \\
List available input scales. Programmable gain amplifier (PGA) options.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **cat in_voltage0_scale_available**
1 0.2
</xterm></WRAP>

=== Set input scale ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/in_voltage0_scale \\
Sets input scale. Controls programmable gain amplifier (PGA).

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **echo 0.2 > in_voltage0_scale**
root:/sys/bus/iio/devices/iio:deviceX> **cat in_voltage0_scale**
0.2
</xterm></WRAP

=== Show internal temperature ===

**__Description:__** /sys/bus/iio/devices/iio:deviceX/in_temp0_input \\
Shows temperature in milli degrees Celsius.

The on-chip temperature sensor allows an accurate measurement of the ambient device temperature.
The measurement range of the sensor is −40°C to +125°C.

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX> **cat in_temp0_input**
27987
</xterm></WRAP>

===== Buffer management =====

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

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

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX/scan_elements> **ls**
in_voltage0_imag_en     in_voltage0_imag_type   in_voltage0_real_index
in_voltage0_imag_index  in_voltage0_real_en     in0_voltage_real_type 
</xterm></WRAP>

{{page>software:linux:docs:iio:iio_snippets#Typical ADC scan elements&noheader&firstseconly&noeditbtn}}

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:/sys/bus/iio/devices/iio:deviceX/scan_elements> **grep "" ***
in_voltage0_imag_en:	1
in_voltage0_imag_index:	1
in_voltage0_imag_type:	s16/16>>0
in_voltage0_real_en:	1
in_voltage0_real_index:	0
in_voltage0_real_type:	s16/16>>0 
</xterm></WRAP>

===== Buffer Example =====

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target - Example command sequence</wrap>
<xterm>
> **cd /sys/bus/iio/devices/iio:device0**
> **echo 10000 > out_voltage0_freq_start**
> **echo 100 > out_voltage0_freq_increment**
> **echo 100 > out_voltage0_freq_points**
> **echo 512 > buffer/length**
> **echo 1 > buffer/enable**
</xterm></WRAP>

==== Data interpretation ====

^ index ^ datum ^ type ^
| 0 | **Real Sample** f0 | signed short 16-bit |
| 1 | **//Imag Sample//** f0 | signed short 16-bit |
| [fn * 2] | **Real Sample** fn | signed short 16-bit |
| [fn * 2] + 1 | **//Imag Sample//** fn | signed short 16-bit |


Z =  **in_voltage0_real** + i * **//in_voltage0_imag//**

<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
<xterm>
root:> **hexdump -d /dev/iio:device0*
0000000   **09451**   **//01627//**   09541   01663   09622   01697   09708   01734
0000010   09799   01757   09889   01791   09985   01820   10079   01856
0000020   10172   01887   10264   01922   10357   01962   10451   02005
0000030   10543   02044   10628   02082   10714   02123   10798   02153
0000040   10889   02188   10983   02230   11069   02268   11157   02302
0000050   11246   02339   11335   02381   11429   02423   11514   02461
0000060   11603   02500   11688   02539   11782   02573   11871   02618
0000070   11955   02659   12045   02703   12135   02743   12221   02787
0000080   12307   02828   12393   02877   12481   02910   12567   02951
0000090   12659   02991   12750   03034   12840   03080   12927   03130
00000a0   13010   03173   13102   03220   13185   03268   13271   03313
00000b0   13356   03358   13443   03401   13525   03445   13612   03491
00000c0   13700   03536   13791   03584   13875   03630   13958   03684
00000d0   14047   03729   14135   03785   14216   03834   14302   03879
00000e0   14383   03930   14469   03982   14555   04028   14634   04084
00000f0   14722   04131   14805   04183   14890   04231   14972   04291
0000100   15052   04340   15136   04389   15216   04445   15301   04495
0000110   15377   04549   15455   04604   15526   04651   15595   04703
0000120   15661   04758   15731   04809   15782   04856   15836   04905
0000130   15885   04943   15939   04990   15993   05043   16035   05083
0000140   16077   05131   16118   05174   16165   05223   16198   05265
0000150   16241   05311   16275   05351   16300   05389   16336   05438
0000160   16373   05482   16405   05522   16441   05559   16470   05603
0000170   16498   05644   16534   05690   16554   05742   16577   05780
0000180   16601   05827   16621   05874   16640   05904   16668   05943
0000190   16686   05983
0000194 
</xterm></WRAP>
====== More Information ======

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

Page Tools
