user
50 lines
1.4 KiB
Markdown
50 lines
1.4 KiB
Markdown
# K13 — EventGroup and coordinated state
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K13 provides a typed `EventMask<Enum>` and `EventGroup<Enum>` over static
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FreeRTOS event-group storage. Wait policy is explicit (`any`/`all`) and clear
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policy is explicit (`keep`/`clear_on_exit`). `WaitResult` retains the snapshot
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returned by the kernel and evaluates it against the requested policy.
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Three workers publish UART, GPIO and APP readiness bits. The coordinator then
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executes a deterministic state sequence:
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```text
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wait all, keep -> snapshot 0x7, current 0x7
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clear GPIO -> clear returns 0x7, current 0x5
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wait all, 3 ticks -> timeout snapshot 0x5, unsatisfied
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wait any UART|APP, clear-> snapshot 0x5, current 0x0
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```
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Setting UART twice leaves the mask at `0x1`, proving an event bit is idempotent
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state and not an occurrence counter.
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## Build
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```sh
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make check
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```
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## Debug
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```gdb
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b event_group_debug_checkpoint
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p g_coordinator_state_seen
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p g_worker_set_result
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p g_uart_repeat_mask
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p/x g_all_snapshot
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p/x g_mask_after_gpio_clear
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p/x g_timeout_snapshot
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p g_timeout_ticks
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p/x g_any_snapshot
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p/x g_final_mask
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p g_event_group_pass
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```
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## Scope boundary
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Bits coordinate state but carry neither payload nor occurrence count. A
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clear-on-exit policy can race with other consumers unless designed explicitly.
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The ISR form of setting bits is not a direct edit of the event group; FreeRTOS
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defers that operation through the timer service path, which is outside this
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task-context card.
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