GD32L233通过I2C总线驱动AHT20温湿度传感器

GD32L23X官方例程没有I2C驱动实例，网上也不太好找，最后整合多方资料，完成了GD32L233KBT6+AHT20的I2C驱动调试。

一、环境准备

1. VSCode+EIDE基础工程（参考GD32L233KBT6开源编译环境搭建）
2. AHT20官方驱动github下载（aht20 drivers）

二、I2C移植

2.1 拷贝文件

拷贝三个文件到工程中：

1. driver_aht20_read_test.c//里面有测试代码可以直接调用，包括初始化和读温湿度
2. driver_aht20.c//aht20驱动
3. driver_aht20_interface_template.c//aht20的i2c底层实现接口
4. 上面三个文件对应的头文件

2.2 移植接口

在i2c读的接口中，需要注意一个地方就是收完字节流后，要加一个延时，不然gd32的stop信号无法正常发出，因此特意增加了一个aht20_interface_delay_us（）函数。
硬件信息是：PB6-SCL, PB7-SDA，通过AF8映射到I2C1。
driver_aht20_interface_template.c是一个空的框架模板，在gd32上实现后的代码如下：

/**
 * Copyright (c) 2015 - present LibDriver All rights reserved
 * 
 * The MIT License (MIT)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE. 
 *
 * @file      driver_aht20_interface_template.c
 * @brief     driver aht20 interface template source file
 * @version   1.0.0
 * @author    Shifeng Li
 * @date      2022-10-31
 *
 * <h3>history</h3>
 * <table>
 * <tr><th>Date        <th>Version  <th>Author      <th>Description
 * <tr><td>2022/10/31  <td>1.0      <td>Shifeng Li  <td>first upload
 * </table>
 */

#include "driver_aht20_interface.h"
#include "gd32l23x_i2c.h"
#include "systick.h"
static void aht20_interface_delay_us(uint32_t us);
/**
 * @brief  interface iic bus init
 * @return status code
 *         - 0 success
 *         - 1 iic init failed
 * @note   none
 */
uint8_t aht20_interface_iic_init(void)
{
   
    // 初始化 I2C1
    rcu_periph_clock_enable(RCU_I2C1);
    rcu_periph_clock_enable(RCU_GPIOB);

    //PB6,PB7通过AF4映射为I2C1
    gpio_af_set(GPIOB, GPIO_AF_8, GPIO_PIN_6);//I2C1_SCL
    gpio_af_set(GPIOB, GPIO_AF_8, GPIO_PIN_7);//I2C1_SDA

    gpio_mode_set(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_6);
    gpio_output_options_set(GPIOB, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, GPIO_PIN_6);
    gpio_mode_set(GPIOB,