电容式触摸传感器

[English]

概述

触摸传感器系统由保护覆盖层、触摸电极、绝缘基板和走线组成，保护覆盖层位于最上层，绝缘基板上设有电极及走线。触摸覆盖层将引起电容变化，根据电容变化，可以判断此次触摸是否为有效触摸行为。

触摸传感器可以以矩阵或滑条等方式组合使用，从而覆盖更大触感区域及更多触感点。触摸传感由软件或专用硬件计时器发起，由有限状态机 (FSM) 硬件控制。

如需了解触摸传感器设计、操作及其控制寄存器等相关信息，请参考《ESP32-S2 技术参考手册》(PDF) 中“片上传感器与模拟信号处理”章节。

请参考 触摸传感器应用方案简介，查看触摸传感器设计详情和固件开发指南。

电容式触摸传感器版本概览

硬件版本	芯片	主要特征
V1	ESP32	第一代触摸传感器，触摸时读数变小
V2	ESP32-S2	第二代触摸传感器，触摸时读数变大 新增防水防潮、接近感应、睡眠唤醒功能
	ESP32-S3	第二代触摸传感器，新增接近感应测量完成中断
V3	ESP32-P4	第三代触摸传感器，新增跳频扫描

触摸通道概览

通道	GPIO
CH0	未引出
CH1	IO1
CH2	IO2
CH3	IO3
CH4	IO4
CH5	IO5
CH6	IO6
CH7	IO7
CH8	IO8
CH9	IO9
CH10	IO10
CH11	IO11
CH12	IO12
CH13	IO13
CH14	IO14

驱动中的术语介绍

• 触摸传感器控制器：触摸传感器驱动的控制器，负责触摸传感器的配置和管理。

• 触摸传感器通道：具体的一路触摸传感器采样通道。一个触摸传感器模块具有多个通道，一般连接到触摸板上，用于测量该触摸板电容的变化。驱动中把对 一个 通道的采样称为 测量，而对 所有 注册通道的 测量 称为一次 扫描。

• 触摸传感器采样配置：触摸传感器采样配置是驱动中对采样有关的硬件配置的统称。采样配置负责触摸传感器通道的采样，其配置决定了触摸通道的充放电次数、充放电频率、测量间隔等。ESP32-S2 仅支持一套采样配置，不支持跳频采样。

文件结构

触摸传感器驱动文件结构图

驱动状态机

下图为触摸传感器驱动的状态机，描述了调用不同函数后驱动的运行状态，以及状态变迁的约束。

触摸传感器驱动状态机示意图

上图为触摸传感器驱动的状态机，描述了调用不同函数后状态的变换关系。其中 <other_configurations> 部分为可选的配置项，包括对触摸驱动控制器和触摸通道的重新配置、回调函数注册等。

备注

touch_channel_read_data() 可在获取触摸通道句柄后（即 INIT 后）任意状态调用，但请注意读数值的有效性。

功能介绍

ESP32-S2 的电容式触摸传感器驱动提供的 API 按功能主要可分为：

• 触摸传感器控制器管理

• 触摸传感器通道管理

• 滤波器配置

• 回调函数

• 启用和禁用

• 连续扫描

• 单次扫描

• 基线值配置

• 测量值读数

• 防水防潮配置

• 接近感应配置

• 睡眠唤醒配置

• 去噪通道配置

触摸传感器控制器管理

触摸传感器驱动通过触摸传感器控制器句柄 touch_sensor_handle_t 控制。调用 touch_sensor_new_controller() 函数即可初始化触摸传感器控制器并得到控制器句柄。

// 有些芯片支持多套采样配置，这里以一套为例
#define SAMPLE_NUM 1
touch_sensor_handle_t sens_handle = NULL;
// 采样配置
touch_sensor_sample_config_t sample_cfg[SAMPLE_NUM] = {
    // 指定采样配置或通过 `TOUCH_SENSOR_Vn_DEFAULT_SAMPLE_CONFIG` 使用默认采样配置
    // ...
};
// 默认控制器配置
touch_sensor_config_t touch_cfg = TOUCH_SENSOR_DEFAULT_BASIC_CONFIG(SAMPLE_NUM, sample_cfg);
// 申请一个新的触摸传感器控制器句柄
ESP_ERROR_CHECK(touch_sensor_new_controller(&touch_cfg, &sens_handle));

删除触摸传感器驱动控制器时需调用 touch_sensor_del_controller() 函数，从而释放该控制器所占用的软硬件资源。注意，需要将基于该控制器申请的其他资源销毁或释放后才能删除该控制器。如该控制器下仍有触摸通道未被删除，则无法直接删除。

ESP_ERROR_CHECK(touch_sensor_del_controller(sens_handle));

在触摸传感器驱动控制器初始化后，且未启用触摸传感器时，可调用 touch_sensor_reconfig_controller() 函数对该控制器进行重新配置。

touch_sensor_config_t touch_cfg = {
    // 控制器的新配置
    // ...
};
ESP_ERROR_CHECK(touch_sensor_reconfig_controller(sens_handle, &touch_cfg));

触摸传感器通道管理

一个触摸传感器具有多个测量通道，每个触摸传感器通道由句柄 touch_channel_handle_t 控制。调用 touch_sensor_new_channel() 函数即可初始化触摸传感器通道并得到通道句柄。

// ...
touch_channel_config_t chan_cfg = {
    // 触摸通道配置
    // ...
};
touch_channel_handle_t chan_handle = NULL;
int chan_id = 0;
// 申请一个新的触摸通道句柄
ESP_ERROR_CHECK(touch_sensor_new_channel(sens_handle, chan_id, &chan_cfg, &chan_handle));

删除触摸传感器通道时需调用 touch_sensor_del_channel() 函数，从而释放该通道所占用的软硬件资源。

ESP_ERROR_CHECK(touch_sensor_del_channel(chan_handle));

在触摸传感器驱动通道初始化后，且未启用触摸传感器时，可调用 touch_sensor_reconfig_channel() 函数对该通道进行重新配置。

touch_channel_config_t chan_cfg = {
    // 触摸通道新配置
    // ...
};
ESP_ERROR_CHECK(touch_sensor_reconfig_channel(chan_handle, &chan_cfg));

滤波器配置

触摸传感器可以通过配置滤波器来提升不同场景下的数据稳定性。调用 touch_sensor_config_filter() 并指定 touch_sensor_filter_config_t 来配置基线值和读数值的滤波策略和更新方式，配置后对所有启用的触摸通道都生效。

若需要注销滤波器，可再次调用 touch_sensor_config_filter() 并将第二个参数（即 touch_sensor_filter_config_t 的配置结构体指针）设为 NULL 来注销滤波器功能。

// ...
touch_sensor_filter_config_t filter_config = {
    // 滤波器配置
    // ...
};
// 注册滤波器
ESP_ERROR_CHECK(touch_sensor_config_filter(sens_handle, &filter_config));
// ...
// 注销滤波器
ESP_ERROR_CHECK(touch_sensor_config_filter(sens_handle, NULL));

回调函数

通过调用 touch_sensor_register_callbacks() 注册各类触摸传感器事件回调函数，当触摸传感器通道触发如触摸 on_active、释放 on_inactive 等事件时，就会调用对应的回调函数通知上层应用，以便对触摸事件进行处理。

例如，测量值超出当前的测量通道的 基线值 + 触发阈值，则该通道将被触发，并调用 on_active 事件的回调函数，通知应用层该触摸通道被 触发。同理，若处于 触发 状态的通道测量值小于 基线值 + 触发阈值，则该通道将回到未触发状态，并调用 on_inactive 事件的回调函数，通知应用层该触摸通道被 释放。

备注

为保证触发和释放事件的稳定性，触摸传感器可配置 触发阈值 的迟滞比较裕量和 去抖动计数 来避免短时间内由噪声和读数抖动引起的反复触发和释放。

具体可注册的回调时间请参考 touch_event_callbacks_t。

touch_event_callbacks_t callbacks = {
    .on_active = example_touch_on_active_cb,
    // 其他回调函数
    // ...
};
// 注册回调函数
ESP_ERROR_CHECK(touch_sensor_register_callbacks(sens_handle, &callbacks, NULL));

// 通过把相应回调设为 NULL 以注销回调函数
callbacks.on_active = NULL;
// 其他需要注销的回调函数
// ...
ESP_ERROR_CHECK(touch_sensor_register_callbacks(sens_handle, &callbacks, NULL));

启用和禁用

配置完成触摸传感器控制器以及通道后，可调用 touch_sensor_enable() 函数启用该控制器，启用后控制器处于 就绪 状态，会对注册的通道上电，可以开始扫描并采集触摸数据。注意，控制器启用后无法更新配置，只能进行扫描采样和读数操作。若要更新配置，需先调用 touch_sensor_disable() 函数禁用控制器，方可重新配置控制器、通道等。

// 启用触摸传感器
ESP_ERROR_CHECK(touch_sensor_enable(sens_handle));
// ...
// 禁用触摸传感器
ESP_ERROR_CHECK(touch_sensor_disable(sens_handle));

连续扫描

在控制器启用后，调用 touch_sensor_start_continuous_scanning() 函数可开始对所有已注册的触摸通道进行连续扫描，每次扫描都会更新对应通道的测量值。调用 touch_sensor_stop_continuous_scanning() 函数后则停止扫描。

// 开始连续扫描
ESP_ERROR_CHECK(touch_sensor_start_continuous_scanning(sens_handle));
// ...
// 停止连续扫描
ESP_ERROR_CHECK(touch_sensor_stop_continuous_scanning(sens_handle));

单次扫描

在控制器启用后，调用 touch_sensor_trigger_oneshot_scanning() 函数可触发一次对所有已注册的触摸通道的扫描。注意，单次扫描为阻塞函数，调用后会保持阻塞直到扫描结束后返回。此外在开始连续扫描后，无法再触发单次扫描。

// 触发单次扫描，并设置超时时间为 1000 ms
ESP_ERROR_CHECK(touch_sensor_trigger_oneshot_scanning(sens_handle, 1000));

基线值配置

一般情况下，不需要额外设置触摸传感器的基线值，若有必要强制复位基线值到当前平滑值，可调用 touch_channel_config_benchmark()。

touch_chan_benchmark_config_t benchmark_cfg = {
    // 基线操作
    // ...
};
ESP_ERROR_CHECK(touch_channel_config_benchmark(chan_handle, &benchmark_cfg));

测量值读数

调用 touch_channel_read_data() 可读取每个通道不同种类的数据，例如基线值、经过滤波后的平滑值等。支持的数据类型请参考 touch_chan_data_type_t。

#define SAMPLE_NUM  1  // 以一套采样配置为例
uint32_t smooth_data[SAMPLE_NUM] = {};
// 读取滤波后的平滑数据
ESP_ERROR_CHECK(touch_channel_read_data(chan_handle, TOUCH_CHAN_DATA_TYPE_SMOOTH, smooth_data));

防水防潮配置

ESP32-S2 支持防水防潮功能。可通过调用 touch_sensor_config_waterproof() 并配置 touch_waterproof_config_t 来注册防水防潮功能。防水防潮功能主要包含两部分：

• 遇水（浸没）保护功能： touch_waterproof_config_t::guard_chan 用于指定用于遇水保护功能的触摸通道，该通道在 PCB 上一般设计成环形，其他普通触摸通道布局在该环形保护圈内，当电路板大面积浸水时，该环形保护通道会被触发，并停止其他触摸通道的扫描，由此防止其他普通通道的误触发；

• 防潮（水滴）屏蔽功能： touch_waterproof_config_t::shield_chan 用于指定防潮屏蔽功能的触摸通道，该通道在 PCB 上一般设计成网格状铺铜。防潮屏蔽通道将与当前测量通道进行同步充放电，当有小水珠覆盖时，通过配置适当的 touch_waterproof_config_t::shield_drv 来提高因水滴造成的电耦合强度，从而识别水滴造成的误触。在实际应用中识别到水滴造成的误触后可适当增加触摸通道触发的阈值来实现通道在水滴覆盖下的正常触发，从而实现防潮功能。

若需要注销防水防潮功能，可再次调用 touch_sensor_config_waterproof() 并将第二个参数（即 touch_waterproof_config_t 的配置结构体指针）设为 NULL 来注销防水防潮功能。

touch_waterproof_config_t waterproof_cfg = {
    // 防水防潮配置
    // ...
};
// 注册防水防潮功能
ESP_ERROR_CHECK(touch_sensor_config_waterproof(sens_handle, &waterproof_cfg));
// ...
// 注销防水防潮功能
ESP_ERROR_CHECK(touch_sensor_config_waterproof(sens_handle, NULL));

接近感应配置

ESP32-S2 支持接近感应功能。可通过调用 touch_sensor_config_proximity_sensing() 并配置 touch_proximity_config_t 来注册接近感应功能。

由于接近感应引起的电容变化远小于物理触摸，PCB 上常用较大面积的铺铜来增大触摸通道的感应面积，另外需要在硬件上对接近感应通道进行多轮扫描并在驱动中进行累加来提高测量灵敏度。接近感应的灵敏度由测量轮数 touch_proximity_config_t::scan_times 决定。测量轮数以及充放电次数越高，灵敏度越高，但是过高的灵敏度容易导致误触发，请选择适当的灵敏度来保证触发的稳定性。

接近感应通道多次测量的累加值也可通过 touch_channel_read_data() 获取，数据类型 touch_chan_data_type_t 为 TOUCH_CHAN_DATA_TYPE_PROXIMITY。

若需要注销接近感应功能，可再次调用 touch_sensor_config_proximity_sensing() 并将第二个参数（即 touch_proximity_config_t 的配置结构体指针）设为 NULL 来注销接近感应功能。

touch_proximity_config_t prox_cfg = {
    // 接近感应配置
    // ...
};
// 注册接近感应功能
ESP_ERROR_CHECK(touch_sensor_config_proximity_sensing(sens_handle, &prox_cfg));
// ...
// 注销接近感应功能
ESP_ERROR_CHECK(touch_sensor_config_proximity_sensing(sens_handle, NULL));

睡眠唤醒配置

ESP32-S2 支持触摸传感器将芯片从 Light-sleep 或 Deep-sleep 状态中唤醒。可通过调用 touch_sensor_config_sleep_wakeup() 并配置 touch_sleep_config_t 来注册接近感应功能。

注册触摸传感器的睡眠唤醒功能后，处于睡眠状态下的芯片仍将继续保持对触摸传感器的采样，这将会导致芯片睡眠后的功耗增加，可通过减少充放电次数、增加采样间隔等方式来降低功耗。

另外，请注意在主核睡眠期间的采样、唤醒等操作均由硬件完成，本驱动由于运行在主核上，无法提供读数、配置等功能。

若需要在睡眠过程中进行读数、配置等操作，可通过运行在 超低功耗协处理器 ULP 上的触摸传感器驱动 components/ulp/ulp_riscv/ulp_core/include/ulp_riscv_touch_ulp_core.h 实现。

• Light-sleep 状态唤醒：通过指定 slp_wakeup_lvl 为 TOUCH_LIGHT_SLEEP_WAKEUP 即可启用触摸传感器 Light-sleep 唤醒功能。注意任何已注册的触摸传感器通道都会在 Light-sleep 状态下保持采样并支持唤醒 Light-sleep。

• Deep-sleep 状态唤醒：启用触摸传感器 Deep-sleep 唤醒功能除了指定 slp_wakeup_lvl 为 TOUCH_DEEP_SLEEP_WAKEUP 外，还需要指定 Deep-sleep 唤醒通道 deep_slp_chan，注意只有该指定的通道才会在 Deep-sleep 状态下保持采样以及唤醒，以此降低在 Deep-sleep 状态下的功耗。此外，若需要在深度睡眠下使用另一套低功耗的配置来进一步降低功耗，可以通过 deep_slp_sens_cfg 额外指定一套低功耗配置，在进入 Deep-sleep 前，驱动会应用这套配置，从 Deep-sleep 状态唤醒后，则会重新配置到之前的配置。请注意当 slp_wakeup_lvl 配置为 TOUCH_DEEP_SLEEP_WAKEUP 后，触摸传感器不仅能唤醒 Deep-sleep 状态，还能唤醒 Light-sleep 状态。

若需要注销睡眠唤醒功能，可再次调用 touch_sensor_config_sleep_wakeup() 并将第二个参数（即 touch_sleep_config_t 的配置结构体指针）设为 NULL 来注销睡眠唤醒功能。

touch_sleep_config_t light_slp_cfg = {
    .slp_wakeup_lvl = TOUCH_LIGHT_SLEEP_WAKEUP,
};
// 注册 Light-sleep 唤醒功能
ESP_ERROR_CHECK(touch_sensor_config_sleep_wakeup(sens_handle, &light_slp_cfg));
// ...
// 注销睡眠唤醒功能
ESP_ERROR_CHECK(touch_sensor_config_sleep_wakeup(sens_handle, NULL));
touch_sleep_config_t deep_slp_cfg = {
    .slp_wakeup_lvl = TOUCH_DEEP_SLEEP_WAKEUP,
    .deep_slp_chan = dslp_chan_handle,
    // 其他 Deep-sleep 唤醒配置
    // ...
};
// 注册 Deep-sleep 唤醒功能
ESP_ERROR_CHECK(touch_sensor_config_sleep_wakeup(sens_handle, &deep_slp_cfg));

去噪通道配置

ESP32-S2 支持通过去噪通道抑制内部背景噪声。可通过调用 touch_sensor_config_denoise_channel() 并配置 touch_denoise_chan_config_t 来注册去噪通道。

去噪通道是一个没有引出的内部触摸通道。去噪通道使能之后，其他触摸通道的采样值会自动减去去噪通道的采样值，从而实现去噪。因此最终测量结果相比去噪前会有一定衰减。

除了常规的触摸通道配置，去噪通道还可以配置 touch_denoise_chan_config_t::ref_cap 来指定连接到该通道上的参考电容大小，以及 touch_denoise_chan_config_t::resolution 来指定噪声抑制的分辨率。分辨率越高，去噪通道采样值越大越精确，抑制效果越好，但同时其他触摸通道在自动扣除去噪通道采样值后的测量值衰减也越大。

例如，去噪通道分辨率为 touch_denoise_chan_resolution_t::TOUCH_DENOISE_CHAN_RESOLUTION_BIT8，即去噪通道采样值最大为 255。假设此时一个常规通道实际采样值为 10000，去噪通道采样值假设为 100，则该常规通道扣除去噪通道采样值后的读数为 10000 - 100 = 9900；若分辨率改为 touch_denoise_chan_resolution_t::TOUCH_DENOISE_CHAN_RESOLUTION_BIT12，即去噪通道采样值最大为 4095，去噪通道分辨率提升 16 倍，去噪通道采样值大概为 100 * 16 = 1600。此时该常规通道扣除去噪通道采样值后的读数为 10000 - 1600 = 8400。

若需要注销去噪通道功能，可再次调用 touch_sensor_config_denoise_channel() 并将第二个参数（即 touch_denoise_chan_config_t 的配置结构体指针）设为 NULL 来注销去噪通道功能。

touch_denoise_chan_config_t denoise_cfg = {
    // 去噪通道配置
    // ...
}
// 注册去噪通道
ESP_ERROR_CHECK(touch_sensor_config_denoise_channel(sens_handle, &denoise_cfg));
// ...
// 注销去噪通道
ESP_ERROR_CHECK(touch_sensor_config_denoise_channel(sens_handle, NULL));

应用示例

• peripherals/touch_sensor/touch_sens_basic 演示了如何注册触摸通道并读取数据，并说明了硬件要求及项目配置。

API 参考

Header File

• components/esp_driver_touch_sens/include/driver/touch_sens.h

• This header file can be included with:

  #include "driver/touch_sens.h"
  

• This header file is a part of the API provided by the esp_driver_touch_sens component. To declare that your component depends on esp_driver_touch_sens, add the following to your CMakeLists.txt:

  REQUIRES esp_driver_touch_sens
  

  or

  PRIV_REQUIRES esp_driver_touch_sens
  

Functions

esp_err_t touch_sensor_new_controller(const touch_sensor_config_t *sens_cfg, touch_sensor_handle_t *ret_sens_handle)

Allocate a new touch sensor controller.

备注

The touch sensor driver will be in INIT state after this function is called successfully.

参数

• sens_cfg -- [in] Touch sensor controller configurations

• ret_sens_handle -- [out] The return handle of the touch controller instance

返回

• ESP_OK On success

• ESP_ERR_NO_MEM No memory for the touch sensor controller

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller is already allocated

esp_err_t touch_sensor_del_controller(touch_sensor_handle_t sens_handle)

Delete the touch sensor controller.

备注

This function can be called when the touch sensor controller is NOT enabled (i.e. INIT state).

参数

sens_handle -- [in] Touch sensor controller handle

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE Controller not disabled or still some touch channels not deleted

esp_err_t touch_sensor_new_channel(touch_sensor_handle_t sens_handle, int chan_id, const touch_channel_config_t *chan_cfg, touch_channel_handle_t *ret_chan_handle)

Allocate a new touch channel from the touch sensor controller.

备注

This function can be called when the touch sensor controller is NOT enabled (i.e. INIT state).

参数

• sens_handle -- [in] Touch sensor controller handle

• chan_id -- [in] Touch channel index

• chan_cfg -- [in] Touch channel configurations

• ret_chan_handle -- [out] The return handle of the touch channel instance

返回

• ESP_OK On success

• ESP_ERR_NO_MEM No memory for the touch sensor channel

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller has not disabled or this channel has been allocated

esp_err_t touch_sensor_del_channel(touch_channel_handle_t chan_handle)

Delete the touch channel.

备注

This function can be called when the touch sensor controller is NOT enabled (i.e. INIT state).

备注

If the channel has been enabled other sub-features like proximity sensing, sleep wakeup, waterproof, denoise. The attached sub-features will be disabled while deleting the channel.

参数

chan_handle -- [in] Touch channel handle

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller has not disabled

esp_err_t touch_sensor_reconfig_controller(touch_sensor_handle_t sens_handle, const touch_sensor_config_t *sens_cfg)

Re-configure the touch sensor controller.

备注

This function can be called when the touch sensor controller is NOT enabled (i.e. INIT state).

备注

The re-configuration only applies to the touch controller, so it requires the controller handle that allocated from touch_sensor_new_controller, meanwhile, it won't affect the touch channels, no matter the channels are allocated or not.

参数

• sens_handle -- [in] Touch sensor controller handle

• sens_cfg -- [in] Touch sensor controller configurations

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller has not disabled

esp_err_t touch_sensor_reconfig_channel(touch_channel_handle_t chan_handle, const touch_channel_config_t *chan_cfg)

Re-configure the touch channel.

备注

This function can be called when the touch sensor controller is NOT enabled (i.e. INIT state).

备注

The re-configuration only applies to a particular touch channel, so it requires the channel handle that allocated from touch_sensor_new_channel

参数

• chan_handle -- [in] Touch channel handle

• chan_cfg -- [in] Touch channel configurations

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller has not disabled

esp_err_t touch_sensor_config_filter(touch_sensor_handle_t sens_handle, const touch_sensor_filter_config_t *filter_cfg)

Configure the touch sensor filter.

备注

This function is allowed to be called after the touch sensor is enabled

参数

• sens_handle -- [in] Touch sensor controller handle

• filter_cfg -- [in] Filter configurations, set NULL to disable the filter

返回

• ESP_OK: Configure the filter success

• ESP_ERR_INVALID_ARG: The sensor handle is NULL

esp_err_t touch_sensor_enable(touch_sensor_handle_t sens_handle)

Enable the touch sensor controller.

备注

This function can be called when the touch sensor controller is NOT enabled (i.e. INIT state). And the touch sensor driver will be in ENABLED state after this function is called successfully.

备注

Enable the touch sensor will power on the registered touch channels

参数

sens_handle -- [in] Touch sensor controller handle

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller has already enabled

esp_err_t touch_sensor_disable(touch_sensor_handle_t sens_handle)

Disable the touch sensor controller.

备注

This function can only be called after the touch sensor controller is enabled (i.e. ENABLED state). And the touch sensor driver will be in INIT state after this function is called successfully.

备注

Disable the touch sensor will power off the registered touch channels

参数

sens_handle -- [in] Touch sensor controller handle

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller has already disabled

esp_err_t touch_sensor_start_continuous_scanning(touch_sensor_handle_t sens_handle)

Start the scanning of the registered touch channels continuously.

备注

This function can only be called after the touch sensor controller is enabled (i.e. ENABLED state). And the touch sensor driver will be in SCANNING state after this function is called successfully. And it can also be called in ISR/callback context.

备注

The hardware FSM (Finite-State Machine) of touch sensor will be driven by its hardware timer continuously and repeatedly. i.e., the registered channels will be scanned one by one repeatedly.

参数

sens_handle -- [in] Touch sensor controller handle

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The touch sensor controller is not enabled or the continuous scanning has started

esp_err_t touch_sensor_stop_continuous_scanning(touch_sensor_handle_t sens_handle)

Stop the continuous scanning of the registered touch channels immediately.

备注

This function can only be called after the continuous scanning started (i.e. SCANNING state). And the touch sensor driver will be in ENABLED state after this function is called successfully. And it can also be called in ISR/callback context.

备注

Stop the hardware timer and reset the FSM (Finite-State Machine) of the touch sensor controller

参数

sens_handle -- [in] Touch sensor controller handle

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

• ESP_ERR_INVALID_STATE The continuous scanning has stopped

esp_err_t touch_sensor_trigger_oneshot_scanning(touch_sensor_handle_t sens_handle, int timeout_ms)

Trigger an oneshot scanning for all the registered channels.

备注

This function can only be called after the touch sensor controller is enabled (i.e. ENABLED state). And the touch sensor driver will be in SCANNING state after this function is called successfully, and then switch back to ENABLED state after the scanning is done or timeout.

备注

The block time of this function depends on various factors, In common practice, recommend to set the timeout to several seconds or wait forever, because oneshot scanning can't last for so long.

参数

• sens_handle -- [in] Touch sensor controller handle

• timeout_ms -- [in] Set a positive value or zero means scan timeout in milliseconds Set a negative value means wait forever until finished scanning

返回

• ESP_OK On success

• ESP_ERR_TIMEOUT Timeout to finish the oneshot scanning

• ESP_ERR_INVALID_ARG Invalid argument

• ESP_ERR_INVALID_STATE The touch sensor controller is not enabled or the continuous scanning has started

esp_err_t touch_sensor_register_callbacks(touch_sensor_handle_t sens_handle, const touch_event_callbacks_t *callbacks, void *user_ctx)

Register the touch sensor callbacks.

备注

This function can be called when the touch sensor controller is NOT enabled (i.e. INIT state).

参数

• sens_handle -- [in] Touch sensor controller handle

• callbacks -- [in] Callback functions

• user_ctx -- [in] User context that will be passed to the callback functions

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG NULL pointer

• ESP_ERR_INVALID_STATE Touch sensor controller has not disabled

esp_err_t touch_channel_config_benchmark(touch_channel_handle_t chan_handle, const touch_chan_benchmark_config_t *benchmark_cfg)

Confiture the touch sensor benchmark for all the registered channels.

备注

This function can be called no matter the touch sensor controller is enabled or not (i.e. ENABLED or SCANNING state). And it can also be called in ISR/callback context.

参数

• chan_handle -- [in] Touch channel handle

• benchmark_cfg -- [in] The benchmark configurations

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG NULL pointer

esp_err_t touch_channel_read_data(touch_channel_handle_t chan_handle, touch_chan_data_type_t type, uint32_t *data)

Read the touch channel data according to the types.

备注

This function can be called no matter the touch sensor controller is enabled or not (i.e. ENABLED or SCANNING state). And it can also be called in ISR/callback context.

备注

Specially, TOUCH_CHAN_DATA_TYPE_PROXIMITY data type will be read from the cached data in the driver, because the proximity data need to be accumulated in several scan times that specified by touch_proximity_config_t::scan_times. For other data types, the data are read from the hardware registers directly (not cached in the driver). The channel data in the register will be updated once the measurement of this channels is done, And keep locked until the next measurement is done.

参数

• chan_handle -- [in] Touch channel handle

• type -- [in] Specify the data type to read

• data -- [out] The data array pointer. If the target supports multiple sample configurations (SOC_TOUCH_SAMPLE_CFG_NUM), the array length should be equal to the frequency hopping number that specified in touch_sensor_config_t::sample_cfg_num, otherwise the array length should be 1.

返回

• ESP_OK On success

• ESP_ERR_INVALID_ARG Invalid argument or NULL pointer

esp_err_t touch_sensor_config_waterproof(touch_sensor_handle_t sens_handle, const touch_waterproof_config_t *wp_cfg)

Configure the touch sensor water proof channels.

备注

Once waterproof is enabled, the other touch channels won't be updated unless the shield channels is activated.

参数

• sens_handle -- [in] Touch sensor controller handle

• wp_cfg -- [in] Water proof channel configurations, set NULL to disable the water proof function

返回

• ESP_OK: Configure the water proof success

• ESP_ERR_INVALID_ARG: The sensor handle is NULL

• ESP_ERR_INVALID_STATE: The touch sensor is enabled

esp_err_t touch_sensor_config_proximity_sensing(touch_sensor_handle_t sens_handle, const touch_proximity_config_t *prox_cfg)

Configure the touch sensor proximity sensing channels.

参数

• sens_handle -- [in] Touch sensor controller handle

• prox_cfg -- [in] Proximity channels configurations, set NULL to disable the proximity sensing

返回

• ESP_OK: Configure the proximity channel success

• ESP_ERR_INVALID_ARG: The sensor handle is NULL

• ESP_ERR_INVALID_STATE: The touch sensor is enabled

esp_err_t touch_sensor_config_sleep_wakeup(touch_sensor_handle_t sens_handle, const touch_sleep_config_t *sleep_cfg)

Configure the touch sensor to wake-up the chip from sleep.

备注

Call this function to enable/disable the touch sensor wake-up the chip from deep/light sleep To only enable the touch sensor wake-up the chip from light sleep, set the touch_sleep_config_t::deep_slp_chan to NULL. During the light sleep, all enabled touch channels will keep working, and any one of them can wake-up the chip from light sleep. To enable the touch sensor wake-up the chip from both light and deep sleep, set the touch_sleep_config_t::deep_slp_chan to an enabled channel. During the deep sleep, only this specified channels can work and wake-up the chip from the deep sleep, and other enabled channels can only wake-up the chip from light sleep.

参数

• sens_handle -- [in] Touch sensor controller handle

• sleep_cfg -- [in] Sleep wake-up configurations, set NULL to disable the touch sensor wake-up the chip from sleep

返回

• ESP_OK: Configure the sleep channel success

• ESP_ERR_INVALID_ARG: The sensor handle is NULL

• ESP_ERR_INVALID_STATE: The touch sensor is enabled

esp_err_t touch_sensor_config_denoise_channel(touch_sensor_handle_t sens_handle, const touch_denoise_chan_config_t *denoise_cfg)

Configure the touch denoise channel.

备注

The denoise channel is used to suppress the internal background noise. Once the denoise channel enabled, the measured data of the other touch channels will minus the data of the denoise channel automatically. So the channel data will be attenuated after enabling the denoise channel.

参数

• sens_handle -- [in] Touch sensor controller handle

• denoise_cfg -- [in] Denoise channel configurations, set NULL to disable the touch channel

返回

• ESP_OK: Configure the denoise channel success

• ESP_ERR_INVALID_ARG: The sensor handle is NULL or invalid denoise configuration

• ESP_ERR_INVALID_STATE: The touch sensor is enabled

Header File

• components/esp_driver_touch_sens/include/driver/touch_sens_types.h

• This header file can be included with:

  #include "driver/touch_sens_types.h"
  

• This header file is a part of the API provided by the esp_driver_touch_sens component. To declare that your component depends on esp_driver_touch_sens, add the following to your CMakeLists.txt:

  REQUIRES esp_driver_touch_sens
  

  or

  PRIV_REQUIRES esp_driver_touch_sens
  

Macros

TOUCH_TOTAL_CHAN_NUM

The total channel number of the touch sensor

TOUCH_SAMPLE_CFG_NUM

The supported max sample configuration number

TOUCH_PROXIMITY_CHAN_NUM

The supported proximity channel number in proximity sensing mode

Type Definitions

typedef struct touch_sensor_s *touch_sensor_handle_t

The handle of touch sensor controller

typedef struct touch_channel_s *touch_channel_handle_t

The handle of touch channel

Enumerations

enum touch_sleep_wakeup_level_t

The chip sleep level that allows the touch sensor to wake-up.

Values:

enumerator TOUCH_LIGHT_SLEEP_WAKEUP

Only enable the touch sensor to wake up the chip from light sleep

enumerator TOUCH_DEEP_SLEEP_WAKEUP

Enable the touch sensor to wake up the chip from deep sleep or light sleep

Header File

• components/esp_driver_touch_sens/hw_ver2/include/driver/touch_version_types.h

• This header file can be included with:

  #include "driver/touch_version_types.h"
  

• This header file is a part of the API provided by the esp_driver_touch_sens component. To declare that your component depends on esp_driver_touch_sens, add the following to your CMakeLists.txt:

  REQUIRES esp_driver_touch_sens
  

  or

  PRIV_REQUIRES esp_driver_touch_sens
  

Structures

struct touch_sensor_sample_config_t

Sample configurations of the touch sensor.

Public Members

uint32_t charge_times

The charge and discharge times of this sample configuration, the read data are positive correlation to the charge_times

touch_volt_lim_h_t charge_volt_lim_h

The upper voltage limit while charging a touch pad. i.e., the touch controller won't charge the touch pad higher than this high voltage limitation.

touch_volt_lim_l_t charge_volt_lim_l

The lower voltage limit while discharging a touch pad. i.e., the touch controller won't discharge the touch pad lower than this low voltage limitation.

touch_idle_conn_t idle_conn

The connection of the idle touch channels. The idle touch channel is a channel which is enabled and power-on but not under measuring.

touch_bias_type_t bias_type

The type of the touch sensor bias. Which affects the charge/discharge stability and power consumption

struct touch_sensor_config_t

Configurations of the touch sensor controller.

Public Members

uint32_t power_on_wait_us

The waiting time between the channels power on and able to measure, to ensure the data stability

float meas_interval_us

Measurement interval of each channels

uint32_t max_meas_time_us

The maximum time of measuring one channel, if the time exceeds this value, the timeout interrupt will be triggered. Set to '0' to ignore the measurement time limitation, otherwise please set a proper time considering the configurations of this sample configurations below.

uint32_t sample_cfg_num

The sample configuration number that used for sampling, CANNOT exceed TOUCH_SAMPLE_CFG_NUM

touch_sensor_sample_config_t *sample_cfg

The array of this sample configuration configurations, the length should be specified in touch_sensor_config_t::sample_cfg_num

struct touch_channel_config_t

Configurations of the touch sensor channel.

Public Members

uint32_t active_thresh[TOUCH_SAMPLE_CFG_NUM]

The active threshold of each sample configuration, while the touch channel smooth value minus benchmark value exceed this threshold, will be regarded as activated

touch_charge_speed_t charge_speed

The speed of charging and discharging the touch pad, the higher the speed, the faster charging and discharging

touch_init_charge_volt_t init_charge_volt

The initial voltage before charging/discharging a touch pad

struct touch_sensor_filter_config_t

Configurations of the touch sensor filter.

Public Members

touch_benchmark_filter_mode_t filter_mode

Benchmark filter mode. IIR filter and Jitter filter can be selected, TOUCH_BM_IIR_FILTER_16 is recommended

uint32_t jitter_step

Jitter filter step size, only takes effect when the filter_mode is TOUCH_BM_JITTER_FILTER. Range: [0 ~ 15]

int denoise_lvl

The denoise level, which determines the noise bouncing range that won't trigger benchmark update. Range: [0 ~ 4]. The greater the denoise_lvl is, more noise resistance will be. Specially, 0 stands for no denoise Typically, recommend to set this field to 1.

struct touch_sensor_filter_config_t::[anonymous] benchmark

Benchmark configuration.

Benchmark filter

touch_smooth_filter_mode_t smooth_filter

Smooth data IIR filter mode

uint32_t active_hysteresis

The hysteresis threshold to judge whether the touch channel is active If the channel data exceed the 'touch_channel_config_t::active_thresh + active_hysteresis' The channel will be activated. If the channel data is below to 'touch_channel_config_t::active_thresh - active_hysteresis' the channel will be inactivated.

uint32_t debounce_cnt

The debounce count of the touch channel. Only when the channel data exceed the touch_channel_config_t::active_thresh + active_hysteresis for debounce_cnt times The channel will be activated. And only if the channel data is below to the touch_channel_config_t::active_thresh - active_hysteresis for debounce_cnt times, the channel will be inactivated. (The unit of debounce_cnt is the tick of the slow clock source)

struct touch_sensor_filter_config_t::[anonymous] data

Data configuration.

Channel data filter

struct touch_sleep_config_t

Configuration of the touch sensor sleep function.

Public Members

touch_sleep_wakeup_level_t slp_wakeup_lvl

The sleep level that can be woke up by touch sensor.

touch_channel_handle_t deep_slp_chan

The touch channel handle that supposed to work in the deep sleep. It can wake up the chip from deep sleep when this channel is activated. Only effective when the touch_sleep_config_t::slp_wakeup_lvl is TOUCH_DEEP_SLEEP_WAKEUP

uint32_t deep_slp_thresh[TOUCH_SAMPLE_CFG_NUM]

The active threshold of the deep sleep channel during deep sleep, while the sleep channel exceed this threshold, it will be regarded as activated Only effective when the touch_sleep_config_t::slp_wakeup_lvl is TOUCH_DEEP_SLEEP_WAKEUP

touch_sensor_config_dslp_t *deep_slp_sens_cfg

Specify the touch sensor configuration during the deep sleep. Note that these configurations will no take effect immediately, they will be set automatically while the chip prepare to enter sleep. Set NULL to not change the configurations before entering sleep. The sleep configuration mainly aims at lower down the charging and measuring times, so that to save power consumption during the sleep. Only effective when the touch_sleep_config_t::slp_wakeup_lvl is TOUCH_DEEP_SLEEP_WAKEUP

struct touch_waterproof_config_t

Configuration of the touch sensor waterproof function.

Public Members

touch_channel_handle_t guard_chan

The guard channel of that used for immersion detect. Set NULL if you don't need the guard channel. Typically, the guard channel is a ring that surrounds the touch panels, it is used to detect the large area that covered by water. While large area of water covers the touch panel, the guard channel will be activated.

touch_channel_handle_t shield_chan

The shield channel that used for water droplets shield, can't be NULL. The shield channel can only be the No.14 channel on touch version 2. Typically, the shield channel uses grid layout which covers the touch area, it is used to shield the influence of water droplets covering both the touch panel and the shield channel. The shield channel will be paralleled to the current measuring channel (except the guard channel) to reduce the influence of water droplets.

uint32_t shield_drv

The shield channel driver, which controls the drive capability of shield channel, range: 0 ~ 7 The larger the parasitic capacitance on the shielding channel, the higher the drive capability needs to be set.

uint32_t immersion_proof

Enable to protect the touch sensor pad when immersion detected. It will temporary disable the touch scanning if the guard channel triggered, and enable again if guard channel released. So that to avoid the fake touch when the touch panel is immersed in water.

struct touch_waterproof_config_t::[anonymous] flags

Flags of the water proof function

struct touch_proximity_config_t

Configuration of the touch sensor proximity function.

Public Members

touch_channel_handle_t proximity_chan[TOUCH_PROXIMITY_CHAN_NUM]

The touch channel handles that will be configured as proximity sensing channels

uint32_t scan_times

The total scan times of EACH sample configuration, all sample configurations share a same scan_times. The measurement result of each scanning will be accumulated together to get the final result.

struct touch_denoise_chan_config_t

Configuration of denoise channel.

Public Members

touch_charge_speed_t charge_speed

The speed of charging and discharging the denoise touch channel, the higher the speed, the faster charging and discharging

touch_init_charge_volt_t init_charge_volt

The initial voltage before starting charging/discharging the denoise channel

touch_denoise_chan_cap_t ref_cap

The reference capacitance of the denoise channel.

touch_denoise_chan_resolution_t resolution

The noise suppression resolution of the denoise channel. The higher the resolution, the better the suppression effect, but at the same time, the attenuation of other touch channel sampling values also increases.

struct touch_base_event_data_t

Base event structure used in touch event queue.

Public Members

touch_channel_handle_t chan

the current triggered touch channel handle

int chan_id

the current triggered touch channel number

uint32_t status_mask

the current channel triggered status. For the bits in the status mask, if the bit is set, the corresponding channel is active if the bit is cleared, the corresponding channel is inactive

struct touch_event_callbacks_t

Touch sensor callbacks.

备注

Set NULL for the used callbacks.

Public Members

bool (*on_active)(touch_sensor_handle_t sens_handle, const touch_active_event_data_t *event, void *user_ctx)

Touch sensor on active event callback. Callback when any touch channel is activated.

Param sens_handle

[in] Touch sensor controller handle, created from touch_sensor_new_controller()

Param event

[in] Touch sensor active event data

Param user_ctx

[in] User registered context, passed from touch_sensor_register_callbacks()

Return

Whether a high priority task has been waken up by this callback function

bool (*on_inactive)(touch_sensor_handle_t sens_handle, const touch_inactive_event_data_t *event, void *user_ctx)

Touch sensor on inactive event callback. Callback when any touch channel is inactivated.

Param sens_handle

[in] Touch sensor controller handle, created from touch_sensor_new_controller()

Param event

[in] Touch sensor inactive event data

Param user_ctx

[in] User registered context, passed from touch_sensor_register_callbacks()

Return

Whether a high priority task has been waken up by this callback function

bool (*on_measure_done)(touch_sensor_handle_t sens_handle, const touch_meas_done_event_data_t *event, void *user_ctx)

Touch sensor on measure done event callback. Callback when the measurement of all the sample configurations on the current touch channel is done.

Param sens_handle

[in] Touch sensor controller handle, created from touch_sensor_new_controller()

Param event

[in] Touch sensor measure done event data

Param user_ctx

[in] User registered context, passed from touch_sensor_register_callbacks()

Return

Whether a high priority task has been waken up by this callback function

bool (*on_scan_done)(touch_sensor_handle_t sens_handle, const touch_scan_done_event_data_t *event, void *user_ctx)

Touch sensor on scan done event callback. Callback when finished scanning all the registered touch channels.

Param sens_handle

[in] Touch sensor controller handle, created from touch_sensor_new_controller()

Param event

[in] Touch sensor scan done event data

Param user_ctx

[in] User registered context, passed from touch_sensor_register_callbacks()

Return

Whether a high priority task has been waken up by this callback function

bool (*on_timeout)(touch_sensor_handle_t sens_handle, const touch_timeout_event_data_t *event, void *user_ctx)

Touch sensor on measurement timeout event callback. Callback when measure the current touch channel timeout.

Param sens_handle

[in] Touch sensor controller handle, created from touch_sensor_new_controller()

Param event

[in] Touch sensor timeout event data

Param user_ctx

[in] User registered context, passed from touch_sensor_register_callbacks()

Return

Whether a high priority task has been waken up by this callback function

bool (*on_proximity_meas_done)(touch_sensor_handle_t sens_handle, const touch_prox_done_event_data_t *event, void *user_ctx)

Touch sensor on proximity sensing measurement done event callback. Callback when proximity sensing measurement of the current channel is done.

Param sens_handle

[in] Touch sensor controller handle, created from touch_sensor_new_controller()

Param event

[in] Touch sensor proximity sensing measure done event data

Param user_ctx

[in] User registered context, passed from touch_sensor_register_callbacks()

Return

Whether a high priority task has been waken up by this callback function

struct touch_chan_benchmark_config_t

Touch sensor benchmark configurations, to set or reset the benchmark of the channel.

Public Members

bool do_reset

Whether to reset the benchmark to the channel's latest smooth data

Macros

TOUCH_MIN_CHAN_ID

This file is only applicable to the touch hardware version2 Version 2 includes ESP32-S2 and ESP32-S3.

The minimum available channel id of the touch pad

TOUCH_MAX_CHAN_ID

The maximum available channel id of the touch pad

TOUCH_SHIELD_CHAN_ID

The touch channel that can be used as the shield channel

TOUCH_SENSOR_DEFAULT_BASIC_CONFIG(sample_cfg_number, sample_cfg_ptr)

Helper macro to the default configurations of the touch sensor controller.

参数

• sample_cfg_number -- [in] The number of the sample configurations, which can only be 1 here because there is only one sample configuration

• sample_cfg_ptr -- [in] The pointer to the sample configurations

TOUCH_SENSOR_V2_DEFAULT_SAMPLE_CONFIG(chg_times, volt_low, volt_high)

Helper macro to the default sample configurations.

备注

This default configuration uses sample frequency = clock frequency / 1

参数

• chg_times -- [in] The charge times of the touch channel

• volt_low -- [in] The low voltage limit of the touch channel

• volt_high -- [in] The high voltage limit of the touch channel

TOUCH_SENSOR_DEFAULT_FILTER_CONFIG()

Helper macro to the default filter configurations.

Type Definitions

typedef touch_sensor_config_t touch_sensor_config_dslp_t

Touch sensor configuration during the deep sleep.

备注

Currently it is the same as the normal controller configuration. The deep sleep configuration only takes effect when the chip entered sleep, so that to update a more power efficient configuration.

typedef touch_base_event_data_t touch_meas_done_event_data_t

Measure done event data.

备注

Currently same as base event data

typedef touch_base_event_data_t touch_scan_done_event_data_t

Scan done event data.

备注

Currently same as base event data

typedef touch_base_event_data_t touch_active_event_data_t

Active event data.

备注

Currently same as base event data

typedef touch_base_event_data_t touch_inactive_event_data_t

Inactive event data.

备注

Currently same as base event data

typedef touch_base_event_data_t touch_prox_done_event_data_t

Proximity sensing measure done event data.

备注

Currently same as base event data

typedef touch_base_event_data_t touch_timeout_event_data_t

Timeout event data.

备注

Currently same as base event data

Enumerations

enum touch_chan_data_type_t

The data type of the touch channel.

Values:

enumerator TOUCH_CHAN_DATA_TYPE_RAW

The raw data of the touch channel

enumerator TOUCH_CHAN_DATA_TYPE_SMOOTH

The smooth data of the touch channel

enumerator TOUCH_CHAN_DATA_TYPE_BENCHMARK

The benchmark of the touch channel

enumerator TOUCH_CHAN_DATA_TYPE_PROXIMITY

The proximity data of the proximity channel

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