6.2. QNX Neutrino

6.2.1. Thread priority

QNX supports a total of 256 scheduling priority levels. A non-root thread can set its priority to a level from 1 to 63 (the highest priority).

Using priorities higher than 63 is only possible if the allowed priority range is changed for non-root processes:

procnto -P priority

For more information’s about changing the priority range refer to the QNX documentation.


Don’t changing the priority range leads to bad timing performance!

6.2.3. IOMMU/SMMU support

For systems that have to use an IOMMU/SMMU for security reasons, it is possible to create predefined typed memory region that is used by the Link Layer. The definition has to be done in the QNX BSP build file and the name must match following pattern:

smm_ LinkLayerName - InstanceNumber(32Bit Hex)

Example: Link Layer emllI8254x with instance number 1

A separate typed memory region must be defined for each Link Layer instance. The typed memory is automatically used by the Link Layer if it matches the pattern, otherwise the default memory is used.

6.2.4. Setting up and running EcMonitorDemo

  1. QNX Neutrino OS configuration

    In order to get real-time priority (e.g. 250), see Thread priority and also set JOBS_PRIORITY. The applications needs root privileges to increase the priority above 63.

  2. Unbind Link Layer instance, e.g.

    ifconfig en1 destroy
  3. Copy files from EC-Master package /bin and eni.xml to directory, e.g. /tmp.

  4. Adjust LD_LIBRARY_PATH search locations for Optimized Link Layers if necessary, e.g.

  5. Run EcMonitorDemo

    cd /tmp
    ./EcMonitorDemo -i8254x 1 1 -f eni.xml

6.2.5. OS Compiler settings

Besides the general settings from Compiling the EcMonitorDemo the following settings are necessary to build the example application for QNX Neutrino.

Extra include paths
Extra source paths
Extra library paths to the main EtherCAT components
Extra libraries