上一章的电容按键完全使用的HAL库的代码,并没有使用线程。这里尝试使用线程来控制电容按键。
依旧是 F767
本来以为会很容易实现,没想到尝试了很久,电容按键一直没有反应。
static rt_uint32_t measure_charge_time(void)
{// 步骤1: 放电 (PA5输出低电平)rt_pin_mode(CAP_KEY_PIN, PIN_MODE_OUTPUT);rt_pin_write(CAP_KEY_PIN, PIN_LOW);rt_hw_us_delay(200); // 充分放电// 步骤2: 切换到输入捕获模式rt_pin_mode(CAP_KEY_PIN, PIN_MODE_INPUT);// 步骤3: 重置计数器并启动捕获__HAL_TIM_SET_COUNTER(&htim2, 0);HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL);// 步骤4: 开始充电rt_pin_write(CAP_KEY_PIN, PIN_HIGH);rt_hw_us_delay(1); // 确保充电开始// 等待捕获完成 (等待10ms)rt_uint32_t start_tick = rt_tick_get();while (__HAL_TIM_GET_FLAG(&htim2, TIM_FLAG_CC1) == RESET) {if ((rt_tick_get() - start_tick) > rt_tick_from_millisecond(10)) {break;}}// 获取捕获值rt_uint32_t capture_value = HAL_TIM_ReadCapturedValue(&htim2, TIM_CHANNEL);HAL_TIM_IC_Stop_IT(&htim2, TIM_CHANNEL);// 清除捕获标志__HAL_TIM_CLEAR_FLAG(&htim2, TIM_FLAG_CC1);return capture_value;
}
上面这一段是原来的,按键捕获函数,也就是靠 这段代码来捕获PA5的上升沿。
然后,函数卡在了
这部分。这是为什么呢?逻辑上没有什么问题。其实很简单,充电错了:
这里是有3.3V电源的。所以不应该 通过PA5充电。
那我们改成PIN_LOW.对吗?
还是不对,要通过使用TIM得到电容按键的充电时间,就需要捕捉上升沿,我们下拉引脚是得不到上升沿的,所以,我们这里需要NOPULL。
可是。。。RTthread的PIN模式里面竟然没有NOPULL
原来是RT直接将 INPUT拆分了。PIN_MODE_INPUT,就是NOPULL。看来我的基础 还需要巩固,引脚的电平模式都还没有区分清楚。
按照上一章配置RTthread后,接下来就是完整的代码:
Tpad_tim2.c:
#include <rtthread.h>
#include <rthw.h>
#include <board.h>
#include <rtdevice.h>
#include <drv_common.h>
//#include <tim.h> // 包含STM32Cube HAL的TIM头文件// 硬件配置
#define CAP_KEY_PIN GET_PIN(A, 5) // PA5引脚
#define TIM_CHANNEL TIM_CHANNEL_1 // TIM2_CH1// 软件配置
#define SAMPLE_INTERVAL 20 // 采样间隔(ms)
#define TOUCH_THRESHOLD 1.2 // 触发阈值倍数
#define CALIBRATION_COUNT 50 // 校准采样次数
#define MAX_CHARGE_TIME 5000 // 最大充电时间(us)static TIM_HandleTypeDef htim2;// 全局状态变量
static rt_uint32_t baseline = 0; // 基准电容值(无触摸)
static struct rt_timer touch_timer; // 触摸定时器
static rt_bool_t touched = RT_FALSE; // 当前触摸状态// 回调函数指针
static void (*key_press_callback)(void) = RT_NULL;
static void (*key_release_callback)(void) = RT_NULL;/*** @brief 设置按键回调函数* @param press_cb 按键按下回调函数* @param release_cb 按键释放回调函数*/
void cap_key_set_callback(void (*press_cb)(void), void (*release_cb)(void))
{key_press_callback = press_cb;key_release_callback = release_cb;
}/*** @brief 初始化TIM2输入捕获*/
static void tim2_capture_init(void)
{// 1. 使能TIM2时钟__HAL_RCC_TIM2_CLK_ENABLE();// 2. 配置基础定时器设置htim2.Instance = TIM2;htim2.Init.Prescaler = 84 - 1; // 84MHz/84 = 1MHz (1us精度)htim2.Init.CounterMode = TIM_COUNTERMODE_UP;htim2.Init.Period = 0xFFFF;htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;if (HAL_TIM_IC_Init(&htim2) != HAL_OK) {rt_kprintf("TIM2 init failed!\n");return;}// 3. 配置输入捕获通道TIM_IC_InitTypeDef sConfigIC = {0};sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;sConfigIC.ICFilter = 0;if (HAL_TIM_IC_ConfigChannel(&htim2, &sConfigIC, TIM_CHANNEL) != HAL_OK) {rt_kprintf("TIM2 channel config failed!\n");return;}// 4. 配置GPIO引脚复用GPIO_InitTypeDef GPIO_InitStruct = {0};__HAL_RCC_GPIOA_CLK_ENABLE();GPIO_InitStruct.Pin = GPIO_PIN_5;GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;GPIO_InitStruct.Alternate = GPIO_AF1_TIM2;HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);// 5. 配置中断HAL_NVIC_SetPriority(TIM2_IRQn, 2, 0);HAL_NVIC_EnableIRQ(TIM2_IRQn);// 6. 启动定时器基础计数HAL_TIM_Base_Start(&htim2);rt_kprintf("TIM2 capture initialized\n");
}/*** @brief 测量充电时间(单位:us)** 使用TIM2的输入捕获功能测量PA5的充电时间*/
static rt_uint32_t measure_charge_time(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};// 步骤1: 放电 (PA5输出低电平)rt_pin_mode(CAP_KEY_PIN, PIN_MODE_OUTPUT);rt_pin_write(CAP_KEY_PIN, PIN_LOW);rt_hw_us_delay(200); // 充分放电// 步骤2: 切换到输入捕获模式rt_pin_mode(CAP_KEY_PIN, PIN_MODE_INPUT);// 步骤3: 重置计数器并启动捕获__HAL_TIM_SET_COUNTER(&htim2, 0);HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_1);// 步骤4: 开始充电//rt_pin_mode(CAP_KEY_PIN, PIN_MODE_INPUT);GPIO_InitStruct.Pin = GPIO_PIN_5;GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;GPIO_InitStruct.Alternate = GPIO_AF1_TIM2;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);rt_hw_us_delay(1); // 确保充电开始// 等待捕获完成 (等待10ms)rt_uint32_t start_tick = rt_tick_get();while (__HAL_TIM_GET_FLAG(&htim2, TIM_FLAG_CC1) == RESET) {// 超时保护if ((rt_tick_get() - start_tick) > rt_tick_from_millisecond(10)) {rt_kprintf("Capture timeout! Counter: %d\n", __HAL_TIM_GET_COUNTER(&htim2));break;}}// 获取捕获值rt_uint32_t capture_value = HAL_TIM_ReadCapturedValue(&htim2, TIM_CHANNEL);HAL_TIM_IC_Stop_IT(&htim2, TIM_CHANNEL);// 清除捕获标志__HAL_TIM_CLEAR_FLAG(&htim2, TIM_FLAG_CC1);return capture_value;
}/*** @brief 高级校准算法*/
static void advanced_calibration(void)
{rt_uint32_t samples[CALIBRATION_COUNT];rt_uint32_t min = 0xFFFFFFFF, max = 0;rt_uint32_t sum = 0;// 第一阶段:采集原始样本for (int i = 0; i < CALIBRATION_COUNT; i++) {samples[i] = measure_charge_time();if (samples[i] < min) min = samples[i];if (samples[i] > max) max = samples[i];sum += samples[i];rt_thread_mdelay(10);}// 第二阶段:剔除异常值(20%边界)rt_uint32_t range = max - min;rt_uint32_t low_bound = min + range / 5;rt_uint32_t high_bound = max - range / 5;rt_uint32_t valid_sum = 0;rt_uint16_t valid_count = 0;for (int i = 0; i < CALIBRATION_COUNT; i++) {if (samples[i] >= low_bound && samples[i] <= high_bound) {valid_sum += samples[i];valid_count++;}}// 第三阶段:设定基准值if (valid_count > (CALIBRATION_COUNT / 3)) {baseline = valid_sum / valid_count;rt_kprintf("Calibrated baseline: %d us\n", baseline);} else {baseline = (min + max) / 2;rt_kprintf("Fallback baseline: %d us\n", baseline);}
}/*** @brief 触摸检测定时器回调函数*/
static void touch_timer_handler(void *parameter)
{rt_uint32_t current_value = measure_charge_time();// 调试输出static int count = 0;if (++count % 1000 == 0) { // 每1000次采样输出一次rt_kprintf("[%d] Current: %d us, Baseline: %d us, Threshold: %d us\n",count, current_value, baseline, (rt_uint32_t)(baseline * TOUCH_THRESHOLD));}// 检测触摸if (current_value > (rt_uint32_t)(baseline * TOUCH_THRESHOLD) &¤t_value < MAX_CHARGE_TIME) {if (!touched) {touched = RT_TRUE;rt_kprintf("TOUCH detected! Value: %d us\n", current_value);// 调用按键按下回调if (key_press_callback) {rt_kprintf("Calling press callback\n");key_press_callback();}}} else {if (touched) {touched = RT_FALSE;rt_kprintf("Touch released\n");// 调用按键释放回调if (key_release_callback) {rt_kprintf("Calling release callback\n");key_release_callback();}}}
}/*** @brief 初始化电容按键功能*/
int cap_key_init(void)
{// 初始化TIM2捕获功能tim2_capture_init();// 初始校准advanced_calibration();// 创建触摸检测定时器rt_timer_init(&touch_timer,"touch_timer",touch_timer_handler,RT_NULL,rt_tick_from_millisecond(SAMPLE_INTERVAL),RT_TIMER_FLAG_PERIODIC | RT_TIMER_FLAG_HARD_TIMER);rt_timer_start(&touch_timer);rt_kprintf("Capacitive key (PA5) initialized!\n");return RT_EOK;
}
INIT_APP_EXPORT(cap_key_init);// 调试命令
static void cap_debug(int argc, char *argv[])
{if (argc > 1) {if (rt_strcmp(argv[1], "measure") == 0) {rt_kprintf("Current value: %d us\n", measure_charge_time());}else if (rt_strcmp(argv[1], "calibrate") == 0) {advanced_calibration();}} else {rt_kprintf("Usage:\n");rt_kprintf("cap_debug measure - Get current value\n");rt_kprintf("cap_debug calibrate - Recalibrate sensor\n");}
}
MSH_CMD_EXPORT(cap_debug, Capacitive key debug tool);/*** @brief TIM2中断处理函数*/
//void TIM2_IRQHandler(void)
//{
// HAL_TIM_IRQHandler(&htim2);
//}
Tpad_tim2.h:
/** Copyright (c) 2006-2021, RT-Thread Development Team** SPDX-License-Identifier: Apache-2.0** Change Logs:* Date Author Notes* 2025-06-26 c the first version*/
#ifndef APPLICATIONS_TPAD_TIM2_H_
#define APPLICATIONS_TPAD_TIM2_H_void cap_key_set_callback(void (*press_cb)(void), void (*release_cb)(void));#endif /* APPLICATIONS_TPAD_TIM2_H_ */
main.c:
#include <rtthread.h>
#include <rtdevice.h>
#include <board.h>
#include <Tpad_tim2.h>#define DBG_TAG "main"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>#define LED_G_PIN GET_PIN(H, 11)// 按键按下处理
static void on_key_press(void)
{rt_kprintf("PRESS\n");rt_pin_mode(LED_G_PIN, PIN_MODE_OUTPUT);rt_pin_write(LED_G_PIN, PIN_LOW);// 执行操作,如点亮LED
}// 按键释放处理
static void on_key_release(void)
{rt_kprintf("RELEASE\n");rt_pin_mode(LED_G_PIN, PIN_MODE_OUTPUT);rt_pin_write(LED_G_PIN, PIN_HIGH);
}int main(void)
{// 设置回调函数cap_key_set_callback(on_key_press, on_key_release);while (1) {rt_thread_mdelay(1000);rt_kprintf("on...\n");}return 0;
}
运行下载后,当手指放上去时,会亮绿灯,手指离开会熄灭。终端也会打印对应的信息。