Difference between revisions of "AS1531"

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== Introduction ==
 
== Introduction ==
  
AS1531 is a 8 channels 12bits analog do digital converter made by [http://www.austriamicrosystems.com/ Austriamicrosystem]. The driver is included in ARMadeus distribution and can be used with the APF51Dev board.
+
AS1531 is a 12bits 8 channels Analog to Digital Converter made by [http://www.austriamicrosystems.com/ Austriamicrosystem]. Its use a SPI bus to communicate with a master microprocessor. A driver is included in the Armadeus BSP/SDK and can be used on the APF51Dev board.
  
== Soldering ==
+
== Connecting chip on APF boards ==
  
AS1531 chip use a SPI bus to communicate with the microprocessor, then to use it on APFx board it must be connected to a SPI bus.
+
* On the [[APF51Dev]], the AS1531 is connected to the SPI1 bus by default, so you can move to [[AS1531#Use_it|next chapter]].
 
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* On the [[APF27Dev]] board it can be soldered on SPI3 bus, which is available on connector J8.
On the APF51Dev, the AS1531 is connected to the SPI1 bus by default, so you can move to next chapter.
+
 
+
On the APF27-Dev board it can be soldered on SPI3 bus, which is availbale on connector J8.
+
  
 
{| class="wikitable" style="text-align:center; width:50%;"
 
{| class="wikitable" style="text-align:center; width:50%;"
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== Driver ==
 
== Driver ==
Driver is by default included if you choose an [[APF51]] as target.
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* Driver is by default included if you choose an [[APF51]] as target.
 
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* Otherwise, you can select it that way:
Otherwise, you can select it that way:
+
  
 
<pre class="host">
 
<pre class="host">
[  ] $ make linux26-menuconfig
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$ make linux-menuconfig
 
</pre>
 
</pre>
  
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</pre>
 
</pre>
  
Then compile the distribution :
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* Then rebuild the Linux and rootfs images:
 
<pre class="host">
 
<pre class="host">
[  ] $ make linux26 && make
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$ make linux && make
 
</pre>
 
</pre>
  
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{{Warning|AS1531 is used with internal reference voltage of 2,5V, so DO NOT TRY to acquire signals with greater voltage range.}}
 
{{Warning|AS1531 is used with internal reference voltage of 2,5V, so DO NOT TRY to acquire signals with greater voltage range.}}
  
=== modprobe ===
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=== Load driver ===
To use the ADC, first load hwmon and as1531 modules:
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To use the AS1531, first load ''as1531'' module:
  
 
<pre class="apf">
 
<pre class="apf">
# modprobe hwmon
 
 
# modprobe as1531
 
# modprobe as1531
 
</pre>
 
</pre>
  
=== read values ===
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=== Read channels value ===
  
 
<pre class="apf">
 
<pre class="apf">
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To read adc value just «cat» an input :
 
To read adc value just «cat» an input :
 
<pre class="apf">
 
<pre class="apf">
# cat in5_input  
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# cat in5_input
 
887
 
887
 
</pre>
 
</pre>
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[[Category:Linux drivers]]
 
[[Category:Linux drivers]]
 
[[Category:Analog to Digital Converter]]
 
[[Category:Analog to Digital Converter]]
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 +
==Examples==
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* Script to read all values each 500ms and display them on console:
 +
<source lang="bash">
 +
#!/bin/sh
 +
 +
modprobe as1531
 +
 +
loop=1
 +
while [ "$loop" == 1 ]; do
 +
        for i in 0 1 2 3 4 5 6 7; do
 +
                value=`cat /sys/bus/spi/devices/spi0.0/in"$i"_input`
 +
                echo -n "$value  "
 +
        done
 +
        usleep 500000  # 500ms
 +
        echo
 +
done
 +
</source>

Latest revision as of 19:13, 12 February 2013

Introduction

AS1531 is a 12bits 8 channels Analog to Digital Converter made by Austriamicrosystem. Its use a SPI bus to communicate with a master microprocessor. A driver is included in the Armadeus BSP/SDK and can be used on the APF51Dev board.

Connecting chip on APF boards

  • On the APF51Dev, the AS1531 is connected to the SPI1 bus by default, so you can move to next chapter.
  • On the APF27Dev board it can be soldered on SPI3 bus, which is available on connector J8.
Soldering schema for SPI3 APF27-dev
J8 pin AS1531 pin
SD1_D0_SPI3_MISO DOUT
SD1_D3_SPI3_SS CSN
SD1_CMD_SPI3_MOSI DIN
SP1_CLK_SPI3_SCLK SCLK

Driver

  • Driver is by default included if you choose an APF51 as target.
  • Otherwise, you can select it that way:
$ make linux-menuconfig
Device Drivers  --->
    <M> Hardware Monitoring support  --->
        <M>   Austria Microsystems AS1531 Analog to Digital Converter
  • Then rebuild the Linux and rootfs images:
$ make linux && make

Use it

Warning Warning: AS1531 is used with internal reference voltage of 2,5V, so DO NOT TRY to acquire signals with greater voltage range.


Load driver

To use the AS1531, first load as1531 module:

# modprobe as1531

Read channels value

# cd /sys/bus/spi/devices/spi0.0/
# ls
driver     in1_input  in4_input  in7_input  modalias   subsystem
hwmon      in2_input  in5_input  in_max     name       uevent
in0_input  in3_input  in6_input  in_min     power

or:

# cd /sys/class/hwmon/hwmon0/device/
# ls
driver     in1_input  in4_input  in7_input  modalias   subsystem
hwmon      in2_input  in5_input  in_max     name       uevent
in0_input  in3_input  in6_input  in_min     power

To read adc value just «cat» an input :

# cat in5_input
887

All values read are in milivolts.

Examples

  • Script to read all values each 500ms and display them on console:
#!/bin/sh

modprobe as1531

loop=1
while [ "$loop" == 1 ]; do
        for i in 0 1 2 3 4 5 6 7; do
                value=`cat /sys/bus/spi/devices/spi0.0/in"$i"_input`
                echo -n "$value  "
        done
        usleep 500000   # 500ms
        echo
done