Difference between revisions of "ADC max1027"

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(Usage)
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The temperature can be read like that
 
The temperature can be read like that
  # cat /sys/bus/spi/drivers/max1027/spi1.0/temp_input
+
  # cat /sys/bus/spi/drivers/max1027/spi1.0/temp1_input
  
 
The two configurations files allow direct access to the corresponding register in the MAX1027.
 
The two configurations files allow direct access to the corresponding register in the MAX1027.

Revision as of 21:15, 20 January 2007

Instructions to install and use the onboard ADC (MAX1027)

Introduction

The MAX1027 is a 8 channels 10 bits A/D converter with integrated temperature sensor. The SPI1 interface is used to communicate with the device. Moreover, the max1027 is registered as a hardware monitor device. For the moment only a low speed interface (/sys) is available. The eight channels and the temperature are updated every 10ms.

Installation

From the top directory:

# make linux-menuconfig

Then select in Device Drivers->Hardware Monitoring Support->MAX1027 sensor chip Once the new config saved, rebuild your image

# make

On the target, the driver can be started like this

# insmod /lib/modules/drivers/hwmon/hwmon.ko
# insmod /lib/modules/drivers/hwmon/max1027.ko


Usage

Several interfaces in /sys/bus/spi/are created in order to

  • read the 8 inputs (inx_input). Result in mV
  • read the temperature (temp_input). Result in deg celsius
  • modify the default configuration (config and conv)

An input can be read like that

# cat /sys/bus/spi/drivers/max1027/spi1.0/in0_input

The temperature can be read like that

# cat /sys/bus/spi/drivers/max1027/spi1.0/temp1_input

The two configurations files allow direct access to the corresponding register in the MAX1027. For more details, take a look at the datasheet