DAC

The Max5821L DAC can be controlled from the user space by using the setDAC function.

Installation

Linux

Activate the necessary I2C drivers in the Linux kernel configuration (modules or builtin):

• -> Device Drivers
• -> I2C support
• -> I2C support -> I2C device interface
• -> I2C support -> I2C Hardware Bus support -> I2C bus on i.MX

By default I2C drivers are builtin in Armadeus Linux kernel

Buildroot

You must enable the max5821ctrl package into your buildroot configuration:
Package Selection for the target->Hardware handling->max5821ctrl

If you are using modules instead of builtin linux drivers, you can check if the modules are loaded with:

# lsmod
i2c_imx                 4008  0
i2c_dev                 5024  0
i2c_core               11472  2 i2c_imx,i2c_dev

Usage

to set the DAC use the setDAC command:

# setDAC

##Usage: setDAC OUTPUT [VALUE]
power down or set DAC output with value 0 - 1023

 OUTPUT is A , B or AB (both)
 VALUE must be 0 - 1023

 If no VALUE is given, then the output is powered down
##

!! Do not forget to connect a voltage reference for the DAC !!

Links

• How to connect Max5821 on your board
• Max5821 Webpage