main/sdk/assembly/TimekeeperConfig/README.md

# TimekeeperConfig

Platform configuration options for the input area.

<table>
    <tr><th>Field</th><th>Type</th><th>Description</th><th>Default</th></tr>
        <tr id="utc_start_at_startup_when_invalid_rtc">
            <td><code>utc_start_at_startup_when_invalid_rtc</code></td>
            <td><code>bool</code></td>
            <td>If set, the UTC clock will be started if we attempt to read the RTC, but the reading of the RTC is known invalid.</td>
            <td></td>
        </tr>
        <tr id="utc_max_allowed_delta_past_sec">
            <td><code>utc_max_allowed_delta_past_sec</code></td>
            <td><code>uint64</code></td>
            <td>Maximum absolute difference between proposed UTC reference and actual UTC reference, expressed in seconds, when the proposed UTC reference is in the "past" with respect of actual UTC reference.

This is always expressed as a non-negative value.</td>
            <td></td>
        </tr>
        <tr id="utc_max_allowed_delta_future_sec">
            <td><code>utc_max_allowed_delta_future_sec</code></td>
            <td><code>uint64</code></td>
            <td>Maximum absolute difference between proposed UTC reference and actual UTC reference, expressed in seconds, when the proposed UTC reference is in the "future" with respect of actual UTC reference.

This is always expressed as a non-negative value.</td>
            <td></td>
        </tr>
        <tr id="use_persistent_storage">
            <td><code>use_persistent_storage</code></td>
            <td><code>bool</code></td>
            <td>If set, assembly should configure and route persistent storage to Timekeeper.</td>
            <td></td>
        </tr>
        <tr id="use_connectivity">
            <td><code>use_connectivity</code></td>
            <td><code>bool</code></td>
            <td>If set, Timekeeper will use connectivity information to gauge whether to sample external time sources or not.</td>
            <td></td>
        </tr>
        <tr id="time_source_endpoint_url">
            <td><code>time_source_endpoint_url</code></td>
            <td><code>string</code></td>
            <td>If set, the device's real time clock is only ever read from, but not written to.</td>
            <td>https://clients3.google.com/generate_204</td>
        </tr>
        <tr id="serve_test_protocols">
            <td><code>serve_test_protocols</code></td>
            <td><code>bool</code></td>
            <td>If set, Timekeeper will serve test-only protocols from the library `fuchsia.time.test`.</td>
            <td></td>
        </tr>
        <tr id="serve_fuchsia_time_external_adjust">
            <td><code>serve_fuchsia_time_external_adjust</code></td>
            <td><code>bool</code></td>
            <td>If set, Timekeeper should serve the FIDL protocol that allows external time adjustment, `fuchsia.time.external/Adjust`.

This is a security sensitive protocol, and very few assemblies are expected to have it turned on.</td>
            <td></td>
        </tr>
        <tr id="serve_fuchsia_time_alarms">
            <td><code>serve_fuchsia_time_alarms</code></td>
            <td><code>bool</code></td>
            <td>If set, Timekeeper will serve `fuchsia.time.alarms` and will connect to the appropriate hardware device to do so.</td>
            <td></td>
        </tr>
        <tr id="rtc_allow_setting_past_utc">
            <td><code>rtc_allow_setting_past_utc</code></td>
            <td><code><a class='link' href="../RtcInitializationPolicy">RtcInitializationPolicy</code></td>
            <td>The policy for how to handle RTC readings that are in the past with respect to the current boot clock.</td>
            <td></td>
        </tr>
        <tr id="power_topology_integration_enabled">
            <td><code>power_topology_integration_enabled</code></td>
            <td><code>bool</code></td>
            <td>If set, timekeeper will use the capabilities related to power management.</td>
            <td></td>
        </tr>
        <tr id="periodic_rtc_update">
            <td><code>periodic_rtc_update</code></td>
            <td><code><a class='link' href="../PeriodicRtcUpdate">PeriodicRtcUpdate</code></td>
            <td>The interval at which the RTC is updated from the UTC clock,</td>
            <td></td>
        </tr>
        <tr id="min_utc_reference_to_backstop_diff_minutes">
            <td><code>min_utc_reference_to_backstop_diff_minutes</code></td>
            <td><code>uint64</code></td>
            <td>If we receive a UTC reference timestamp that is less than this amount of time away from backstop, we reject it.</td>
            <td>20</td>
        </tr>
        <tr id="first_sampling_delay_sec">
            <td><code>first_sampling_delay_sec</code></td>
            <td><code>int64</code></td>
            <td>The time to wait before sampling the time source for the first time, expressed in seconds.</td>
            <td></td>
        </tr>
        <tr id="back_off_time_between_pull_samples_sec">
            <td><code>back_off_time_between_pull_samples_sec</code></td>
            <td><code>int64</code></td>
            <td>The time to wait until retrying to sample the pull time source, expressed in seconds.</td>
            <td>300</td>
        </tr>
        <tr id="always_on_counter">
            <td><code>always_on_counter</code></td>
            <td><code>bool</code></td>
            <td>If set, the hardware has a counter that is always on and operates even if the rest of the hardware system is in a low power state.</td>
            <td></td>
        </tr>
</table>