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When the C166 microcontroller was introduced, Siemens (now Infineon) created the first C compiler available for this architecture. The Siemens Task Concept was an effort to ease modular program development by adding an extra level of scope between functions in a program that could be grouped into separate tasks or task groups.

The Keil L166 Linker supports TGROUPS (Task Groups) which allow you to isolate symbols, sections, interrupts, and groups from different object modules. You may specify the task name as well as a list of object modules for each TGROUP.

The format for the L166 Linker command line using TGROUPS is:

L166 <[>task-name<]> {input-list <[>tgroup-controls<]>}
     { , ... }
     <[>input-list<]> <[>TO output-file<]> <[>directives<]>


task-name is a TGROUP identifier used in the µVision Debugger or an emulator. Note that curly-braces ('{}') enclose the object files in each task group.
input-list is a comma-separated list of object files as described in the Command Prompt section.
tgroup-controls may be any of the following L166 Linker directives that reference public symbols, sections, or groups in the object files in the TGROUP: ASSIGN, GROUPS, INTNO, SECSIZE, and SECTIONS.
output-file is the name of the absolute object file the linker creates as described in the Command Prompt section.
directives are commands and parameters that control the operation of the linker. A complete list of directives is found in the Directives section.


  • While the Siemens Task Concept limits the number of interrupt procedures within a Siemens Task, TGROUPS are used by L166 to isolate symbols, sections, and groups from different TGROUPS.
  • TGROUPS isolate symbols, sections, interrupt names, and group names from other modules. Therefore, the ASSIGN, GROUPS, INTNO, SECSIZE, and SECTIONS directives must be applied to the same section name in each TGROUP separately. These directives may be used within the TGROUP braces ('{') and ('}'). When used within a TGROUP these directives refer only to sections defined inside that TGROUP.
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