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The AVR Context
[RTOS Implementation Building Blocks]

A context switch requires the entire execution context to be saved. On the AVR microcontroller the context consists of:
  • 32 general purpose processor registers. The gcc development tools assume register R1 is set to zero.
  • Status register. The value of the status register affects instruction execution, and must be be preserved across context switches.
  • Program counter. Upon resumption, a task must continue execution from the instruction that was about to be executed immediately prior to its suspension.
  • The two stack pointer registers.

    AVRContext.gif


Next: RTOS Implementation – Saving The Context


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