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Diffstat (limited to 'docs/reference')
| -rw-r--r-- | docs/reference/isr_rules.rst | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/docs/reference/isr_rules.rst b/docs/reference/isr_rules.rst index 7f466ab42..a611f492a 100644 --- a/docs/reference/isr_rules.rst +++ b/docs/reference/isr_rules.rst @@ -339,8 +339,8 @@ A critical section can comprise a single line of code and a single variable. Con This example illustrates a subtle source of bugs. The line ``count += 1`` in the main loop carries a specific race condition hazard known as a read-modify-write. This is a classic cause of bugs in real time systems. In the main loop -MicroPython reads the value of ``t.counter``, adds 1 to it, and writes it back. On rare occasions the interrupt occurs -after the read and before the write. The interrupt modifies ``t.counter`` but its change is overwritten by the main +MicroPython reads the value of ``count``, adds 1 to it, and writes it back. On rare occasions the interrupt occurs +after the read and before the write. The interrupt modifies ``count`` but its change is overwritten by the main loop when the ISR returns. In a real system this could lead to rare, unpredictable failures. As mentioned above, care should be taken if an instance of a Python built in type is modified in the main code and |