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doc: gpio glitch filter
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morris
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@ -105,7 +105,6 @@ api-reference/peripherals/secure_element
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api-reference/peripherals/ledc
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api-reference/peripherals/sdio_slave
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api-reference/peripherals/clk_tree
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api-reference/peripherals/sdm
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api-reference/peripherals/touch_pad
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api-reference/peripherals/adc_calibration
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api-reference/peripherals/ds
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@ -68,6 +68,7 @@ INPUT = \
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$(PROJECT_PATH)/components/driver/include/driver/dedic_gpio.h \
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$(PROJECT_PATH)/components/driver/include/driver/gpio.h \
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$(PROJECT_PATH)/components/driver/include/driver/gpio_etm.h \
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$(PROJECT_PATH)/components/driver/include/driver/gpio_filter.h \
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$(PROJECT_PATH)/components/driver/include/driver/gptimer.h \
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$(PROJECT_PATH)/components/driver/include/driver/gptimer_etm.h \
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$(PROJECT_PATH)/components/driver/include/driver/gptimer_types.h \
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@ -21,6 +21,36 @@ GPIO Summary
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:SOC_ULP_SUPPORTED: - The :doc:`Ultra Low Power co-processor <../../api-reference/system/ulp>` is running
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- Analog functions such as ADC/DAC/etc are in use.
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER or SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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GPIO Glitch Filter
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------------------
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The {IDF_TARGET_NAME} chip features hardware filters to remove unwanted glitch pulses from the input GPIO, which can help reduce false triggering of the interrupt and prevent a noise being routed to the peripheral side.
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER
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Each GPIO can be configured with a glitch filter, which can be used to filter out pulses shorter than **two** sample clock cycles. The duration of the filter is not configurable. The sample clock is the clock source of the IO-MUX. In the driver, we call this kind of filter as "pin glitch filter". You can create the filter handle by calling :cpp:func:`gpio_new_pin_glitch_filter`. All the configurations for a pin glitch filter are listed in the :cpp:type:`gpio_pin_glitch_filter_config_t` structure.
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- :cpp:member:`gpio_pin_glitch_filter_config_t::gpio_num` sets the GPIO number to enable the glitch filter.
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.. only:: SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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{IDF_TARGET_FLEX_GLITCH_FILTER_NUM:default="8"}
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{IDF_TARGET_NAME} provides {IDF_TARGET_FLEX_GLITCH_FILTER_NUM} flexible glitch filters, whose duration is configurable. We refer to this kind of filter as "flex flitch filter". Each of them can be applied to any input GPIO. However, applying multiple filters to the same GPIO doesn't make difference from one. You can create the filter handle by calling :cpp:func:`gpio_new_flex_glitch_filter`. All the configurations for a flexible glitch filter are listed in the :cpp:type:`gpio_flex_glitch_filter_config_t` structure.
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- :cpp:member:`gpio_flex_glitch_filter_config_t::gpio_num` sets the GPIO that will be applied the flex glitch filter.
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- :cpp:member:`gpio_flex_glitch_filter_config_t::window_width_ns` and :cpp:member:`gpio_flex_glitch_filter_config_t::window_thres_ns` are the key parameters of the glitch filter. During :cpp:member:`gpio_flex_glitch_filter_config_t::window_width_ns`, any pulse whose width is shorter than :cpp:member:`gpio_flex_glitch_filter_config_t::window_thres_ns` will be discarded. Please note that, you can't set :cpp:member:`gpio_flex_glitch_filter_config_t::window_thres_ns` bigger than :cpp:member:`gpio_flex_glitch_filter_config_t::window_width_ns`.
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER and SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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Please note, the "pin glitch filter" and "flex glitch filter" are independent. You can enable both of them for the same GPIO.
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The glitch filter is disabled by default, and can be enabled by calling :cpp:func:`gpio_glitch_filter_enable`. To recycle the filter, you can call :cpp:func:`gpio_del_glitch_filter`. Please note, before deleting the filter, you should disable it first by calling :cpp:func:`gpio_glitch_filter_disable`.
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Application Example
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-------------------
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@ -40,3 +70,11 @@ API Reference - Normal GPIO
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.. include-build-file:: inc/rtc_io.inc
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.. include-build-file:: inc/rtc_io_types.inc
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER or SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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API Reference - GPIO Glitch Filter
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----------------------------------
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.. include-build-file:: inc/gpio_filter.inc
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@ -21,6 +21,35 @@ GPIO 汇总
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:SOC_ULP_SUPPORTED: - :doc:`超低功耗协处理器 (ULP) <../../api-reference/system/ulp>` 运行时
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- 使用 ADC/DAC 等模拟功能时
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER or SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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GPIO 毛刺过滤器
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---------------
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{IDF_TARGET_NAME} 内置硬件的过滤器可以帮助过滤掉 GPIO 输入端口上的毛刺信号, 这可以一定程度上避免错误地触发中断或者是错把噪声当成有效的外设信号。
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER
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每个 GPIO 都可以使用独立的毛刺过滤器，该过滤器可以将那些脉冲宽度窄于 **2** 个采样时钟的信号剔除掉， 并且这个宽度是无法配置的。GPIO 对输入信号的采样时钟通常是 IO-MUX 的时钟源。在驱动中， 我们将此类过滤器称为 “pin glitch filter“。 你可以调用 :cpp:func:`gpio_new_pin_glitch_filter` 函数来创建一个过滤器句柄。过滤器的相关配置保存在 :cpp:type:`gpio_pin_glitch_filter_config_t` 结构体中。
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- :cpp:member:`gpio_pin_glitch_filter_config_t::gpio_num` 设置哪个 GPIO 需要开启毛刺过滤器。
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.. only:: SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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{IDF_TARGET_FLEX_GLITCH_FILTER_NUM:default="8"}
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{IDF_TARGET_NAME} 提供了 {IDF_TARGET_FLEX_GLITCH_FILTER_NUM} 个灵活的毛刺过滤器， 被过滤信号的脉冲宽度可以由软件进行配置。我们称此类过滤器为 "flex flitch filter"。每个过滤器可以分配给任意一个 GPIO, 但是将多个过滤器应用在同一个 GPIO 上并不能带来更好的效果。你可以调用 :cpp:func:`gpio_new_flex_glitch_filter` 函数来创建一个过滤器句柄。过滤器的相关配置保存在 :cpp:type:`gpio_flex_glitch_filter_config_t` 结构体中。
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- :cpp:member:`gpio_flex_glitch_filter_config_t::gpio_num` 设置哪个 GPIO 需要使用毛刺过滤器。
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- :cpp:member:`gpio_flex_glitch_filter_config_t::window_width_ns` 和 :cpp:member:`gpio_flex_glitch_filter_config_t::window_thres_ns` 是毛刺过滤器的关键参数。在:cpp:member:`gpio_flex_glitch_filter_config_t::window_width_ns` 时间内，任何脉冲信号，如果它的宽度小于 :cpp:member:`gpio_flex_glitch_filter_config_t::window_thres_ns`, 那么该脉冲信号就会被滤除掉。:cpp:member:`gpio_flex_glitch_filter_config_t::window_thres_ns` 的值不能大于 :cpp:member:`gpio_flex_glitch_filter_config_t::window_width_ns`。
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER and SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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请注意， "pin glitch filter" 和 "flex glitch filter" 是各自独立的，你可以给同一个 GPIO 同时启用他们两种滤波器。
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毛刺滤波器默认情况下是处于关闭状态的， 你需要调用 :cpp:func:`gpio_glitch_filter_enable` 去使能它。如果要回收这个过滤器，你可以调用 :cpp:func:`gpio_del_glitch_filter` 函数。注意， 在你回收过滤器句柄之前， 请确保它是处于关闭状态的，如果不是，你需要调用 :cpp:func:`gpio_glitch_filter_disable`。
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应用示例
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-------------------
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@ -40,3 +69,10 @@ API 参考 - 普通 GPIO
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.. include-build-file:: inc/rtc_io.inc
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.. include-build-file:: inc/rtc_io_types.inc
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.. only:: SOC_GPIO_SUPPORT_PIN_GLITCH_FILTER or SOC_GPIO_FLEX_GLITCH_FILTER_NUM
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API 参考 - GPIO 毛刺过滤器
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--------------------------
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.. include-build-file:: inc/gpio_filter.inc
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