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RX8111 Binary Sensor

The rx8111 binary sensor platform reports the latched flags and live status of an RX8111 real-time clock. Configure that time component and its I²C bus first.

# Example configuration entry
binary_sensor:
  - platform: rx8111
    vlf:
      name: "RTC Voltage Low Flag"

Configuration Variables

Section titled “Configuration Variables”
  • rx8111_id (Optional, ID): The RX8111 time component. Required when more than one RX8111 is configured.
  • vlf (Optional): The latched voltage-low flag (FLAG.VLF). On means the RTC reports low-voltage history and its time is not trusted. Defaults to the problem device class.
  • alarm_flag (Optional): The latched alarm flag (FLAG.AF). On means an alarm match has been recorded.
  • timer_flag (Optional): The latched timer flag (FLAG.TF). On means a timer expiration has been recorded.
  • xst (Optional): The latched oscillator-stop flag (FLAG.XST). On means an oscillator stop was detected, not that the oscillator is healthy. Defaults to the problem device class.
  • event_flag (Optional): The latched EVIN event flag (FLAG.EVF). On means an event has been recorded.
  • battery_low (Optional): The live backup-voltage status (STATUS.VLOW). On means the backup voltage at VBAT is below the chip’s detection threshold. This is not a battery percentage. Defaults to the battery device class. Detection must already be enabled using EVLOW in register 0x35; this component leaves that setting unchanged and does not provide a YAML option to enable it. An off state does not establish battery health when detection is disabled.
  • evin (Optional): The sampled physical EVIN input level (STATUS.EVIN). On means high and off means low, independently of the configured event polarity. Short pulses between polls can be missed.

All seven sensor options are optional, but at least one must be configured. Put all sensors for one clock in a single rx8111 binary sensor platform block. Multiple clocks can each have their own block and rx8111_id. Each sensor accepts all options from Binary Sensor and defaults to the diagnostic entity category.

Polling and Flag Handling

Section titled “Polling and Flag Handling”

Status is read at startup and using the time component’s event_poll_interval (default 1s, minimum 500ms), even when update_interval: never disables periodic calendar synchronization. There is no separate binary-sensor update interval. A failed register read preserves the previous states for that register’s sensors; an initial failed read leaves them unknown. A failed FLAG read does not prevent live STATUS sensors from updating, and a failed STATUS read does not prevent FLAG sensors from updating.

These sensors report raw flags independently of whether the corresponding alarm, timer, or event callback is enabled. Reading or publishing a flag does not clear it. Use the time component’s alarm actions, timer actions, or rx8111.clear_event_flag action to acknowledge the corresponding flag. A successful rx8111.write_time clears the time-invalid flags, including VLF and XST. Cleared states are reported on the next status read.

Binary-sensor automations run before the corresponding time-component event callbacks. Clearing a flag from a synchronous binary-sensor automation can suppress the matching on_alarm, on_timer, or on_event callback in that poll. If both are needed, acknowledge the flag only after the required handling is complete.

Adding these sensors does not enable or reconfigure alarms, the timer, EVIN event detection, timestamp capture, backup switching, or charging. Configure those features on the time component or timestamp text sensor separately. Binary status sensors and the timestamp text sensor can be used together on the same clock.

See Also

Section titled “See Also”