arduino ide esp32 light-sleep代码

下面是一个简单的Arduino IDE示例代码，演示如何在ESP32上使用Light-sleep模式：

#include <esp_sleep.h>

void setup() {
  Serial.begin(115200);
  Serial.println("Entering Light-sleep mode...");
  esp_sleep_enable_timer_wakeup(5000000); // 5秒后唤醒
  esp_light_sleep_start();
}

void loop() {
  // 这里的代码不会被执行，因为ESP32进入了Light-sleep模式
}

在这个示例中，我们使用`esp_sleep_enable_timer_wakeup()`函数设置了一个5秒钟的定时器唤醒。然后，我们调用`esp_light_sleep_start()`函数进入Light-sleep模式。ESP32将进入低功耗状态，CPU将关闭，但RTC和ULP协处理器仍可运行。经过5秒钟后，ESP32将自动唤醒并继续执行`setup()`函数后面的代码。

需要注意的是，在Light-sleep模式下，GPIO引脚和外设的状态将被保留，因此需要根据具体情况配置GPIO和外设的状态。同时，也需要注意Light-sleep模式的唤醒源，比如通过定时器、GPIO中断、UART等方式唤醒。

相关问题

esp32-c3 gpio hold

### ESP32-C3 GPIO Hold Configuration and Functionality

For the ESP32-C3, configuring GPIO pins to be held at a certain state during reset or deep sleep is crucial for maintaining system stability and ensuring that specific hardware configurations persist through power cycles or low-power states[^1]. The `GPIO hold` function allows developers to lock the level of GPIOs when entering light-sleep mode or deep-sleep mode.

To configure GPIO hold on an ESP32-C3 device:

#### Enabling GPIO Hold via Software

The SDK provides APIs specifically designed for setting up GPIO holds. Below is an example demonstrating how to enable this feature using C code within the Arduino IDE environment or IDF framework.

#include "driver/gpio.h"

void setup_gpio_hold(int gpio_num){
    // Enable GPIO hold capability.
    gpio_set_direction(gpio_num, GPIO_MODE_DISABLE);
    gpio_pullup_dis(gpio_num);
    gpio_pulldown_dis(gpio_num);

    // Set initial value before holding it.
    gpio_set_level(gpio_num, 0); // Or use 1 depending on your requirement
    
    // Finally apply hold command.
    gpio_hold_en(gpio_num);
}

This snippet ensures that once configured, the specified pin will retain its logic level even after waking from sleep modes until explicitly released with `gpio_hold_dis()`.

Moreover, regarding flexibility in usage scenarios, as mentioned previously about programmable properties where each IO line can serve multiple purposes like PWM generation, ADC input/output among others based upon software settings[^3].

In cases such as insufficient numbers of available general-purpose inputs/outputs (as encountered while designing schematics), alternative solutions involve repurposing special-function terminals into standard digital lines whenever possible without compromising core functionalities—like assigning VDD_SPI also known as GPIO11 for I2C communication tasks instead[^2].

--related questions--

1. How does enabling GPIO hold affect current consumption during different operating modes?
2. What are some best practices when deciding which GPIO should have their levels preserved across resets?
3. Can all types of GPIO operations coexist alongside those being held simultaneously? If not, what limitations exist?
4. Are there any considerations one must take into account when reassigning specialized pins like VDD_SPI to generic roles?
5. Is it feasible to implement custom wake-up sources directly connected to these held-state outputs?

stm32f103c8t6 ESP32

### STM32F103C8T6与ESP32微控制器特性对比

#### 1. 性能指标
STM32F103C8T6基于ARM Cortex-M3内核，运行频率可达72 MHz；而ESP32则采用双核 Xtensa LX6 微处理器架构，最高工作频率为240 MHz。显然，在处理能力方面，ESP32具有明显优势[^1]。

#### 2. 存储资源
STM32F103C8T6内置64 KB Flash 和20 KB SRAM；相比之下，ESP32拥有更大的存储空间——通常配备520KB SRAM (其中TCM RAM占240KB)，并且支持外部SPI/SDIO flash接口来扩展程序和数据存储容量。

#### 3. 外设功能
两者都具备丰富的外设接口选项，但具体种类有所不同。例如：

- **定时器**：STM32系列提供了多个高级定时器用于精确计时操作；
- **ADC/DAC**：STM32有12位精度的模数转换器(Analog-to-Digital Converter, ADC)以及DAC输出通道；
- **通信接口**：除了常见的UART/SPI/IIC之外，ESP32还集成了Wi-Fi和蓝牙模块，这使得它在网络连接性能上有很大提升[^2]。

#### 4. 功耗管理
对于低功耗需求的应用场景来说，两款MCU都有各自的优化措施。然而，由于ESP32内部集成更多复杂的功能单元（如无线收发机），其静态电流会稍高于STM32F103C8T6。不过，在某些特殊模式下（比如轻度睡眠模式Light Sleep Mode），两者的能耗差异不大。

#### 5. 开发生态系统和支持工具链
STM32家族背后有着强大的ST官方技术支持团队，并且围绕该系列产品形成了庞大的社区交流平台和技术文档资料库。与此同时，Arduino IDE也很好地兼容了这两款芯片，方便初学者快速入门编程实践。值得注意的是，ESP-IDF作为Espressif Systems专门为ESP32设计的一套SDK框架，则进一步增强了后者在物联网领域内的竞争力。

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### 应用场景分析

鉴于上述技术规格上的区别，当考虑选用哪一款MCU时应综合评估目标项目的实际需求：

- 如果项目侧重于本地计算密集型任务或是对成本敏感的小批量生产，则可以选择性价比更高的STM32F103C8T6。

- 对于那些依赖稳定可靠的互联网接入服务、需要频繁与其他智能终端交互或者追求更广泛市场认可度的产品而言，ESP32可能是更好的选择。