diff --git a/docs/conf_common.py b/docs/conf_common.py index 3b7275ee56..427f703223 100644 --- a/docs/conf_common.py +++ b/docs/conf_common.py @@ -39,6 +39,7 @@ BLE_DOCS = [ 'api-guides/ble/get-started/ble-connection.rst', 'api-guides/ble/get-started/ble-data-exchange.rst', 'api-guides/ble/smp.rst', + 'api-guides/low-power-mode/low-power-mode-ble.rst', 'api-reference/bluetooth/bt_le.rst', 'api-reference/bluetooth/esp_gap_ble.rst', 'api-reference/bluetooth/esp_gatt_defs.rst', diff --git a/docs/en/api-guides/ble/index.rst b/docs/en/api-guides/ble/index.rst index 80530e8262..e9deeee59f 100644 --- a/docs/en/api-guides/ble/index.rst +++ b/docs/en/api-guides/ble/index.rst @@ -13,6 +13,7 @@ Overview overview ble-feature-support-status ble-qualification + Low Power Mode Introduction <../low-power-mode/low-power-mode-ble> *************** Get Started diff --git a/docs/en/api-guides/low-power-mode/index.rst b/docs/en/api-guides/low-power-mode/index.rst index c8d4734efb..6b21653564 100644 --- a/docs/en/api-guides/low-power-mode/index.rst +++ b/docs/en/api-guides/low-power-mode/index.rst @@ -13,3 +13,4 @@ The standby power consumption plays an important role in embedded IoT applicatio low-power-mode-soc :SOC_WIFI_SUPPORTED: low-power-mode-wifi + :SOC_BLE_SUPPORTED: low-power-mode-ble diff --git a/docs/en/api-guides/low-power-mode/low-power-mode-ble.rst b/docs/en/api-guides/low-power-mode/low-power-mode-ble.rst new file mode 100644 index 0000000000..636c3076f4 --- /dev/null +++ b/docs/en/api-guides/low-power-mode/low-power-mode-ble.rst @@ -0,0 +1,210 @@ +Introduction to Low Power Mode in Bluetooth\ :sup:`®` Low Energy Scenarios +================================================================================ + +:link_to_translation:`zh_CN:[中文]` + +This section introduces clock source selection in low power modes for Bluetooth Low Energy (BLE), along with common related issues. + +Clock Source Selection in Low Power Mode +-------------------------------------------- + +According to the Bluetooth specification, the sleep clock accuracy must be within 500 PPM, so make sure the clock source selected for BLE low power mode should meet that requirement. Otherwise BLE may not perform normally and cause a series of problem such as ACL connection establishment failure or ACL connection timeout, etc. + + +Selecting Main XTAL +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To select the main XTAL as the BLE internal clock source, configure the following option: + +.. only:: esp32 or esp32c3 or esp32s3 + + **Configuration Path:** + + ``Component config → Bluetooth → Controller Options → MODEM SLEEP Options → Bluetooth modem sleep → Bluetooth Modem sleep Mode 1 → Bluetooth low power clock`` + + **Configuration Option:** + + - \ (X) Main crystal + +.. only:: esp32c2 or esp32c6 or esp32h2 or esp32c5 or esp32c61 + + **Configuration Path:** + + ``Component config → Bluetooth → Controller Options → BLE low power clock source`` + + **Configuration Option:** + + - \ (X) Use main XTAL as RTC clock source + +When this is selected, the main XTAL remains powered on during light-sleep, resulting in higher current consumption. The current reference for light-sleep using XTAL versus a 32kHz external crystal is shown below: + +.. list-table:: Current Reference Values for Different Clock Sources in Light-sleep Mode + :widths: auto + :header-rows: 1 + + * - Clock Source + - Typical Light-sleep Current + * - Main XTAL + - 3.3 mA + * - 32kHz External Crystal / 136 kHz RC + - 34 uA + + +Selecting 32kHz External Crystal +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To use a 32kHz external crystal as the BLE internal clock source, configure the following options: + +.. only:: esp32 or esp32c3 or esp32s3 + + **Configuration Path:** + + ``Component config → Bluetooth → Controller Options → MODEM SLEEP Options → Bluetooth modem sleep → Bluetooth Modem sleep Mode 1 → Bluetooth low power clock`` + + **Configuration Option:** + + - \ (X) External 32kHz crystal/oscillator + +.. only:: esp32c2 or esp32c6 or esp32h2 or esp32c5 or esp32c61 + + **Configuration Path 1:** + + ``Component config → Bluetooth → Controller Options → BLE low power clock source`` + + **Configuration Option:** + + - \ (X) Use system RTC slow clock source + + **Configuration Path 2:** + + ``Component config → Hardware Settings → RTC Clock Config → RTC clock source`` + + **Configuration Option:** + + - \ (X) External 32 kHz crystal + +**Note:** Even if 32kHz is selected in menuconfig, the system will fall back to the main XTAL if the external crystal is not detected during BLE initialization. This may lead to unexpected current consumption in light-sleep mode. + + +Selecting 136 kHz RC Oscillator +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. only:: esp32c3 or esp32s3 + + To use a 136 kHz internal RC oscillator as the BLE internal clock source, configure the following option: + + **Configuration Path:** ` + + `Component config → Bluetooth → Controller Options → MODEM SLEEP Options → Bluetooth modem sleep → Bluetooth Modem sleep Mode 1 → Bluetooth low power clock`` + + **Configuration Option:** + + - \ (X) Internal 136kHz RC oscillator + + Generally, the 136 kHz RC oscillator cannot meet the accuracy requirement of BLE. It is only suitable for scenarios with low clock accuracy requirements, such as legacy advertising (ADV) or scanning. + + However, for testing purposes, if the peer device also uses 136 kHz RC as the clock source, BLE can function under a 136 kHz RC clock through the following configuration: + + **Configuration Path:** + + ``Component config → Bluetooth → Controller Options`` + + **Configuration Options:** + + - \ [*] Enable to set constant peer SCA + - \ (3000) Constant peer sleep clock accuracy value + + **Note:** Using the 136 kHz RC oscillator may cause rare issues like connection drops or failures to establish a connection. + +.. only:: esp32 + + **Note:** ESP32 does not support using 136 kHz RC oscillator as the BLE clock source. + +.. only:: esp32c2 or esp32c6 or esp32h2 or esp32c5 or esp32c61 + + To use a 136 kHz internal RC oscillator as the BLE internal clock source, configure the following options: + + **Configuration Path 1:** + + ``Component config → Bluetooth → Controller Options → BLE low power clock source`` + + **Configuration Option:** + + - \ (X) Use system RTC slow clock source + + **Configuration Path 2:** + + ``Component config → Hardware Settings → RTC Clock Config → RTC clock source`` + + **Configuration Option:** + + - \ (X) Internal 136 kHz RC oscillator + + Generally, the 136 kHz RC oscillator cannot meet the accuracy requirement of BLE. It is only suitable for scenarios with low clock accuracy requirements, such as legacy advertising (ADV) or scanning. + + If low curent consumption is required but have no access to the External 32kHz Crystal, then this clock source is recommended. However, selecting this clock source will have the sleep clock accuracy larger than 500 PPM, which is supported if the peer device is also an ESP chip. If the peer device is not an ESP chip, here's some BLE event not supported: + + 1. Central role of Connection + 2. Advertiser of Periodic Advertising + + If the peer device also uses 136 kHz RC as the clock source, the following configuration should be set: + + **Configuration Path:** + + ``Component config → Bluetooth → Controller Options`` + + **Configuration Options:** + + - \ [*] Enable to set constant peer SCA + - \ (3000) Constant peer sleep clock accuracy value + + **Note:** Using the 136 kHz RC oscillator may cause rare issues like connection establishment failure or connection timeout. + + +**How to Check the Current Clock Source Used by BLE** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +You can determine the BLE clock source from the logs during BLE initialization: + +.. list-table:: BLE Initialization Log Messages and Clock Source Correspondence + :widths: 50 50 + :header-rows: 1 + + * - Log Message + - Clock Source + * - Using main XTAL as clock source + - Main XTAL + * - Using 136 kHz RC as clock source + - Internal 136 kHz RC oscillator + * - Using external 32.768 kHz crystal as clock source + - External 32 kHz crystal + * - Using external 32.768 kHz oscillator at 32K_XP pin as clock source + - External 32 kHz oscillator at 32K_XP pin + + +FAQ +-------------------------------------- + +**1. BLE ACL Connection Fails or Disconnects in Low Power Mode** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +As explained in the clock source selection section above, when ACL connections fail to establish or unexpectedly disconnect in low power mode, first verify whether the current clock source meets BLE accuracy requirements. + + +**2. Measured light-sleep Current Is Higher Than Expected** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +As introduced in the clock source selection section above, if the main XTAL is used as the clock source, it will remain powered on during light-sleep, resulting in higher current consumption than other clock sources. + +Also, BLE operates in Auto Light-sleep mode, meaning the system decides whether to enter sleep after entering IDLE. During advertising or scanning, current will be significantly higher than during light-sleep. + +Thus, the average current in low power mode is somewhere between light-sleep current and peak current (usually TX current). + +The average current can be application specific, and depends on the BLE configuration and the period of time in light-sleep mode. Some application may have larger average currrent because it has BLE taking a larger ratio of time transmitting and receiving. + +**3. Unable to Enter light-sleep Mode** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +When Auto light-sleep is enabled but the device fails to enter light-sleep, it's often due to insufficient IDLE duration, which prevents meeting the automatic light-sleep entry conditions. + +This could be caused by excessive logging or BLE configuration that prevents sufficient IDLE time, such as continuous scan mode. diff --git a/docs/zh_CN/api-guides/ble/index.rst b/docs/zh_CN/api-guides/ble/index.rst index 287977cea2..201911777f 100644 --- a/docs/zh_CN/api-guides/ble/index.rst +++ b/docs/zh_CN/api-guides/ble/index.rst @@ -13,6 +13,7 @@ overview ble-feature-support-status ble-qualification + 低功耗模式介绍 <../low-power-mode/low-power-mode-ble> ********** 快速入门 diff --git a/docs/zh_CN/api-guides/low-power-mode/index.rst b/docs/zh_CN/api-guides/low-power-mode/index.rst index 8c1d526cfe..efa345c3be 100644 --- a/docs/zh_CN/api-guides/low-power-mode/index.rst +++ b/docs/zh_CN/api-guides/low-power-mode/index.rst @@ -13,3 +13,4 @@ low-power-mode-soc :SOC_WIFI_SUPPORTED: low-power-mode-wifi + :SOC_BLE_SUPPORTED: low-power-mode-ble diff --git a/docs/zh_CN/api-guides/low-power-mode/low-power-mode-ble.rst b/docs/zh_CN/api-guides/low-power-mode/low-power-mode-ble.rst new file mode 100644 index 0000000000..9e2c8f7d25 --- /dev/null +++ b/docs/zh_CN/api-guides/low-power-mode/low-power-mode-ble.rst @@ -0,0 +1,210 @@ +低功耗蓝牙\ :sup:`®` 场景下低功耗模式介绍 +======================================================================== + +:link_to_translation:`en:[English]` + +本节介绍低功耗蓝牙 (Bluetooth LE) 在低功耗模式下的时钟源选择，以及常见相关问题。 + +低功耗模式下的时钟源选择 +-------------------------------------------- + +在低功耗蓝牙应用场景中，由于协议要求休眠时钟精度需在 500 PPM 以内，light-sleep 和 modem-sleep 模式下所用的时钟源必须满足该要求。如果时钟精度不足，可能会出现 ACL 连接失败或超时断开等问题。**因此在使用前请确保所选时钟源及其精度满足 BLE 要求。** + + +选择主晶振 +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +要选择主晶振作为 BLE 内部时钟源，请配置以下选项： + +.. only:: esp32 or esp32c3 or esp32s3 + + **配置路径：** + + ``Component config → Bluetooth → Controller Options → MODEM SLEEP Options → Bluetooth modem sleep → Bluetooth Modem sleep Mode 1 → Bluetooth low power clock`` + + **配置选项：** + + - \ (X) Main crystal + +.. only:: esp32c2 or esp32c6 or esp32h2 or esp32c5 or esp32c61 + + **配置路径：** + + ``Component config → Bluetooth → Controller Options → BLE low power clock source`` + + **配置选项：** + + - \ (X) Use main XTAL as RTC clock source + +选择主晶振后，light-sleep 模式下主晶振电源不会关闭，因此电流消耗更高。使用 XTAL 和 32kHz 外部晶振时 light-sleep 电流参考如下： + +.. list-table:: light-sleep 模式下不同时钟源的电流参考值 + :widths: auto + :header-rows: 1 + + * - 时钟源 + - 典型 light-sleep 电流 + * - 主晶振 + - 3.3 mA + * - 32kHz 外部晶振 / 136 kHz RC + - 34 uA + + +选择 32kHz 外部晶振 +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +要使用 32kHz 外部晶振作为 BLE 内部时钟源，请配置以下选项： + +.. only:: esp32 or esp32c3 or esp32s3 + + **配置路径：** + + ``Component config → Bluetooth → Controller Options → MODEM SLEEP Options → Bluetooth modem sleep → Bluetooth Modem sleep Mode 1 → Bluetooth low power clock`` + + **配置选项：** + + - \ (X) External 32kHz crystal/oscillator + +.. only:: esp32c2 or esp32c6 or esp32h2 or esp32c5 or esp32c61 + + **配置路径 1：** + + ``Component config → Bluetooth → Controller Options → BLE low power clock source`` + + **配置选项：** + + - \ (X) Use system RTC slow clock source + + **配置路径 2：** + + ``Component config → Hardware Settings → RTC Clock Config → RTC clock source`` + + **配置选项：** + + - \ (X) External 32 kHz crystal + +**注意：** 即使在 menuconfig 中选择了 32kHz 外部晶振，如果 BLE 初始化时未检测到外部晶振，系统会自动切换为主晶振，可能导致 light-sleep 电流高于预期。 + + +选择 136 kHz RC 振荡器 +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. only:: esp32c3 or esp32s3 + + 要使用 136 kHz 内部 RC 振荡器作为 BLE 内部时钟源，请配置以下选项： + + **配置路径：** + + ``Component config → Bluetooth → Controller Options → MODEM SLEEP Options → Bluetooth modem sleep → Bluetooth Modem sleep Mode 1 → Bluetooth low power clock`` + + **配置选项：** + + - \ (X) Internal 136kHz RC oscillator + + 一般来说，136 kHz RC 振荡器难以满足 BLE 的精度要求，仅适用于对时钟精度要求不高的场景，如传统广播 (ADV) 或扫描 (SCAN)。 + + 但测试时，如果对端设备也用 136 kHz RC 作为时钟源，可通过如下配置实现 BLE 在 136 kHz RC 下运行： + + **配置路径：** + + ``Component config → Bluetooth → Controller Options`` + + **配置选项：** + + - \ [*] Enable to set constant peer SCA + - \ (3000) Constant peer sleep clock accuracy value + + **注意：** 使用 136 kHz RC 振荡器可能偶发连接断开或连接失败。 + +.. only:: esp32 + + **注意：** ESP32 不支持 136 kHz RC 振荡器作为 BLE 时钟源。 + +.. only:: esp32c2 or esp32c6 or esp32h2 or esp32c5 or esp32c61 + + 要使用 136 kHz 内部 RC 振荡器作为 BLE 内部时钟源，请配置以下选项： + + **配置路径 1：** + + ``Component config → Bluetooth → Controller Options → BLE low power clock source`` + + **配置选项：** + + - \ (X) Use system RTC slow clock source + + **配置路径 2：** + + ``Component config → Hardware Settings → RTC Clock Config → RTC clock source`` + + **配置选项：** + + - \ (X) Internal 136 kHz RC oscillator + + 一般来说，136 kHz RC 振荡器难以满足 BLE 的精度要求，仅适用于对时钟精度要求不高的场景，如传统广播 (ADV) 或扫描 (SCAN)。 + + 对于需要低功耗且没有32kHz外部晶振的场景下，可以选择136 kHz RC振荡器。然而这个时钟无法满足BLE的500PPM的休眠时钟精度需求。不过如果对端设备使用的是ESP芯片，仍能支持BLE行为。但是如果对端设备并非使用ESP芯片，则使用下面BLE行为将无法支持： + + 1. 作为连接的Central方 + 2. 作为Periodic Advertising的广播方 + + 如果对端设备也用 136 kHz RC 作为时钟源，需要如下配置: + + **配置路径：** + + ``Component config → Bluetooth → Controller Options`` + + **配置选项：** + + - \ [*] Enable to set constant peer SCA + - \ (3000) Constant peer sleep clock accuracy value + + **注意：** 使用 136 kHz RC 振荡器可能偶发连接断开或连接失败。 + + +**如何确认当前 BLE 使用的时钟源** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +可通过 BLE 初始化时的日志判断当前时钟源： + +.. list-table:: BLE 初始化日志与时钟源对应关系 + :widths: 50 50 + :header-rows: 1 + + * - 日志内容 + - 时钟源 + * - Using main XTAL as clock source + - 主晶振 (Main XTAL) + * - Using 136 kHz RC as clock source + - 内部 136 kHz RC 振荡器 (Internal 136 kHz RC oscillator) + * - Using external 32.768 kHz crystal as clock source + - 外部 32 kHz 晶振 (External 32 kHz crystal) + * - Using external 32.768 kHz oscillator at 32K_XP pin as clock source + - 外部 32 kHz 振荡器 (32K_XP 引脚) (External 32 kHz oscillator at 32K_XP pin) + + +常见问题 +-------------------------------------- + +**1. BLE ACL 连接在低功耗模式下建立失败或断开** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +如时钟源选择部分所述，ACL 连接建立失败或断开时，请首先检查当前时钟源是否满足 BLE 精度要求。 + + +**2. 实测 light-sleep 电流高于预期** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +如时钟源选择部分所述，若主晶振为时钟源，light-sleep 模式下主晶振持续供电，电流消耗高于其他时钟源。 + +此外，BLE 运行在 Auto Light-sleep 模式下，系统在进入 IDLE 后自动决定是否休眠。广播或扫描时电流远高于 light-sleep。 + +因此，低功耗模式下的平均电流介于 light-sleep 电流与峰值电流（通常为 TX 电流）之间。 + +一个应用程序的平均电流一般取决于在light-sleep模式下的时间，以及蓝牙的配置。如果一个应用中蓝牙收发包的时间更长，这个应用的平均电流也会更高 + +**3. 无法进入 light-sleep 模式** +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +启用 Auto light-sleep 后，若设备无法进入 light-sleep，通常是 IDLE 时间不足，未满足自动进入条件。 + +这可能由日志过多或 BLE 配置导致 IDLE 时间过短（如连续扫描）引起。