Echelon FTXL User Manual

Page 174

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162

FTXL LonTalk API

Figure 13. FTXL Abstract Priorities

Before you can instantiate a task within an application, you must map the FTXL
OSAL abstract priorities to the operating system’s priorities. The abstract

priorities are defined in the FtxlOsal.h file that is copied to your project directory
by the LonTalk Interface Developer utility.
To map the FTXL OSAL abstract priorities to the operating system’s priorities,

use the macros that are defined in the FtxlOsal.h file, as listed in Table 32. The
FTXL OSAL reserves room between the high and medium FTXL tasks for high

priority application tasks, and between the medium and low FTXL tasks for
medium priority tasks. The relationships between these macros are shown in

Figure 14 on page 163.

Table 32. Macros for Operating System Task Priorities

Macro

Description

OS_HIGH_PRIORITY_BASE

Defines the OS priority number of the

highest priority task used by the FTXL
OSAL.

OS_APPLICATION_HIGH_PRIORITY_BASE Defines the highest OS priority used for

high priority application tasks.
These tasks should have a higher priority

than the FTXL OSAL medium priority
tasks, but lower than the OSAL high

priority tasks.

OS_MEDIUM_PRIORITY_BASE

Defines the highest OS priority used for

medium priority FTXL tasks.

These tasks should have a higher priority

than normal application tasks, but lower

than the application high priority tasks.

OS_APPLICATION_PRIORITY_BASE

Defines the highest OS priority used for

normal application tasks.

These tasks should have a higher priority

than FTXL OSAL low priority tasks, but

lower than the FTXL OSAL medium priority
tasks.

OS_LOW_PRIORITY_BASE

Defines the highest OS priority used for low
priority tasks.

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