Using Lothron with DIMM-MX6

Attention: Only use Lothron with DIMM-MX6 if you need to test a device that can not be connected to the Cadun baseboard!

Power supply issue

The high CPU/GPU performance of DIMM-MX6 compared to the previous core modules from emtrion leads to higher power consumption. The DIMM-MX6 module can demand more power under certain circumstances than the Lothron base board can deliver. The Lothron base can handle at most 5Volts@2Ampère=10Watt. This limit is already surpassed if you have the UMSH8272 display power plug connected to Lothron and start the GPU demo available in our launcher.
So we recommend the following precautions:

  1. Limit the power supply to 10 Watts
    Instead of using a standard power supply use one where you can limit the current to 2A. If the board will demand more than 2A, this will result in a reset of the board since the breakdown of the power, but it will help to prevent damaging the DC/DC converters of Lothron. The Lothron also has an on-board polyfuse which will cause a reset if a high current is drawn for a longer time, but limiting the current with the power supply is better because the power supply immediately causes a reset.
  2. USB Host: Use a self-powered HUB
    Only connect a self-powered USB-Hub to Lothron and connect all USB devices you want to use to this hub. This prevents USB devices using additional power from Lothron.
  3. Use a display connected to the DVI port of Lothron
    Instead of using the developer kit display which is directly connected to Lothron and also receives its power from Lothron, you can connect a DVI-capable monitor to the DVI port of Lothron base. Have a look at the section DVI-Setup below. Then you can disconnect the display from Lothron which saves additional power.
  4. Reduce the maximum CPU core clock rate and number of used CPU cores
    Of course, power demand depends on how many CPU cores are used and on what their maximum clock frequency is. The following link explains how to adjust these parameters: http://www.support.emtrion.de/doku.php?id=emsdk:mx6_cpu_core_handling

If and how many of the above measures you have to apply highly depends on your application. If your application doesn’t use the GPU at all, you should even be fine with the standard Lothron developer kit and the attached display. If you are experiencing hard resets while testing your application it is an indicator that you use more power than Lothron can deliver. Then you have to apply one or more of the above mentioned workarounds.

DVI-Setup

If you want to use the DVI output on our Lothron baseboard you first have to edit uboot_script. This file is found under ${ROOTFS}/boot. In this file, you have to edit the kernel boot argument for the display driver in the “uboot_script_net_boot” and “uboot_script_flash_boot” command. Coming from us the boot argument will look like this:

video=mxcfb0:dev=lcd,800x480,if=RGB666,bpp=16

You have to change the resolution to the resolution of your screen with an added “M@60”. E.g. for 1024×768:

video=mxcfb0:dev=lcd,1024x768M@60,if=RGB666,bpp=16

Attention: The DVI-converter chip on Lothron can not handle a resolution higher than 1600×900 pixels.
Now you have to boot the linux system. Execute the shell script “lothron_dvi_setup.sh” and you should see the output on the monitor connected to Lothron.

lothron_dvi_setup.sh