修改readme，添加说明

This reverts commit fecaa256ca875a88d75a33249926d835c4ddafe0.

CMakeLists.txt

@@ -3,6 +3,20 @@ include(cmake/toolchain.cmake)
 
 project(gd32e23x_template)
 
+set(VERSION_MAJOR 0)
+set(VERSION_MINOR 0)
+set(VERSION_PATCH 1)
+set(VERSION "V${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH}")
+string(TIMESTAMP CURRENT_DATE "%Y-%m-%d")
+
+# Options 1
+set(OPT1 "")
+#set(OPT1 "_[SW_IIC]")
+
+# Options 2
+set(OPT2 "")
+#set(OPT2 "_[NO_LED]")
+
 enable_language(C)
 enable_language(CXX)
 enable_language(ASM)
@@ -18,7 +32,11 @@ set(TARGET_C_SRC
         ${CMAKE_SOURCE_DIR}/src/main.c
         ${CMAKE_SOURCE_DIR}/src/gd32e23x_it.c
         ${CMAKE_SOURCE_DIR}/src/systick.c
-        ${CMAKE_SOURCE_DIR}/src/peripheral.c
+        ${CMAKE_SOURCE_DIR}/src/led.c
+        ${CMAKE_SOURCE_DIR}/src/usart.c
+        ${CMAKE_SOURCE_DIR}/src/soft_i2c.c
+        ${CMAKE_SOURCE_DIR}/src/i2c.c
+        ${CMAKE_SOURCE_DIR}/src/fwdgt.c
 )
 
 add_executable(gd32e23x_template ${TARGET_C_SRC})

README.md

@@ -1,7 +1,25 @@
 # gd32e23x_template
-本项目为GD32E230Fx系列的基于Clion的CMake开发的工程模板。本人暂未入门，强行上强度，放弃keil，拥抱开源。遂尝试使用arm-none-eabi-gcc进行开发。
+本项目为`GD32E230Fx`系列的基于Clion的CMake开发的工程模板。本人暂未入门，强行上强度，放弃keil，拥抱开源。遂尝试使用arm-none-eabi-gcc进行开发。
 有幸寻得[@mo10 ](https://github.com/mo10)大佬的帮助，本项目的基础目录架构与CMakeLists.txt与toolchain.cmake均为大佬提供。
 
+## 关于本项目
+本项目默认的芯片型号为`GD32E230F4`，但是可以根据需要修改为其他型号，具体修改方法请参考下方`关于链接脚本`的说明。
+### 版本号
+默认版本号为`0.0.1`，在`CMakeLists.txt`中修改`PROJECT_VERSION`即可。
+### 项目名称
+默认项目名称为`gd32e23x_template`，在`CMakeLists.txt`中修改`PROJECT_NAME`即可。请先修改项目名称再配置编译环境。
+### 软件IIC与硬件IIC
+本项目中提供了软件IIC与硬件IIC的驱动，但是默认使用硬件IIC，如果需要使用软件IIC，请在`board_config.h`中取消注释`// #define SOFTWARE_IIC`(line 8)。
+### 编译选项
+本项目预留了两个编译选项，`OPT1`与`OPT2`，默认均为空，请根据需要自行修改，例如`OPT1`为`_[HW_IIC]`，`OPT2`为`_[NO_LED]`。
+`OPT1`与`OPT2`均在`CMakeLists.txt`中可修改。
+### 关于编译日期
+本项目在`CMakeLists.txt`中添加了编译日期。
+
+### 关于led
+本项目默认开启了LED闪烁，并使用TIMER16进行定时。
+
+
 ## 关于C标准库的printf的重写
 在Keil开发中，ARMClang有自己的microLIB，所以直接调用，然后重写fputc函数即可，但在gcc中需要重写`_write`函数，本项目模板中已经在`main.c`中完成重写。
 同时需要添加`--spaces=nano.spaces`编译参数。
@@ -15,7 +33,6 @@ set(TARGET_C_SRC
         ${CMAKE_SOURCE_DIR}/src/main.c
         ${CMAKE_SOURCE_DIR}/src/gd32e23x_it.c
         ${CMAKE_SOURCE_DIR}/src/systick.c
-        ${CMAKE_SOURCE_DIR}/src/peripheral.c
 )
 ```
 ## 关于链接脚本

cmake/toolchain.cmake

@@ -41,12 +41,12 @@ function(print_size_of_target TARGET)
             )
 endfunction()
 
-function(_generate_file TARGET OUTPUT_EXTENSION OBJCOPY_BFD_OUTPUT)
+function(_generate_file TARGET VERSION CURRENT_DATE OPT1 OPT2 OUTPUT_EXTENSION OBJCOPY_BFD_OUTPUT)
     get_target_property(TARGET_OUTPUT_NAME ${TARGET} OUTPUT_NAME)
     if (TARGET_OUTPUT_NAME)
-        set(OUTPUT_FILE_NAME "${TARGET_OUTPUT_NAME}.${OUTPUT_EXTENSION}")
+        set(OUTPUT_FILE_NAME "${TARGET_OUTPUT_NAME}_${VERSION}_${CURRENT_DATE}${OPT1}${OPT2}.${OUTPUT_EXTENSION}")
     else()
-        set(OUTPUT_FILE_NAME "${TARGET}.${OUTPUT_EXTENSION}")
+        set(OUTPUT_FILE_NAME "${TARGET}_${VERSION}_${CURRENT_DATE}${OPT1}${OPT2}.${OUTPUT_EXTENSION}")
     endif()
 
     get_target_property(RUNTIME_OUTPUT_DIRECTORY ${TARGET} RUNTIME_OUTPUT_DIRECTORY)
@@ -66,11 +66,11 @@ function(_generate_file TARGET OUTPUT_EXTENSION OBJCOPY_BFD_OUTPUT)
 endfunction()
 
 function(generate_binary_file TARGET)
-    _generate_file(${TARGET} "bin" "binary")
+    _generate_file(${TARGET} "${VERSION}" "${CURRENT_DATE}" "${OPT1}" "${OPT2}" "bin" "binary")
 endfunction()
 
 function(generate_hex_file TARGET)
-    _generate_file(${TARGET} "hex" "ihex")
+    _generate_file(${TARGET} "${VERSION}" "${CURRENT_DATE}" "${OPT1}" "${OPT2}" "hex" "ihex")
 endfunction()
 
 set(CMAKE_EXECUTABLE_SUFFIX_C   .elf)

inc/board_config.h

@@ -0,0 +1,47 @@
+//
+// Created by dell on 24-12-28.
+//
+
+#ifndef BOARD_CONFIG_H
+#define BOARD_CONFIG_H
+
+// #define SOFTWARE_IIC
+
+// #define DEBUG_VERBOES
+
+/******************************************************************************/
+
+#define I2C_GPIO_RCU         RCU_GPIOF
+#define I2C_RCU              RCU_I2C0
+#define I2C_PHY              I2C0
+#define I2C_SCL_PORT         GPIOF
+#define I2C_SCL_PIN          GPIO_PIN_1
+#define I2C_SDA_PORT         GPIOF
+#define I2C_SDA_PIN          GPIO_PIN_0
+#define I2C_GPIO_AF          GPIO_AF_1
+
+/******************************************************************************/
+
+#define USART_GPIO_RCU       RCU_GPIOA
+#define USART_RCU            RCU_USART0
+#define USART_GPIO_PORT      GPIOA
+#define USART_GPIO_AF        GPIO_AF_1
+#define USART_TX_PIN         GPIO_PIN_2
+#define USART_RX_PIN         GPIO_PIN_3
+#define USART_PHY            USART0
+#define USART_PHY_BAUDRATE   115200U
+#define RS485_EN_PORT        GPIOA
+#define RS485_EN_PIN         GPIO_PIN_1
+
+/******************************************************************************/
+
+#define LED_PORT             GPIOA
+#define LED_PIN              GPIO_PIN_7
+#define LED_RCU              RCU_GPIOA
+#define LED_BLINK_TIMER_RCU  RCU_TIMER16
+#define LED_BLINK_TIMER      TIMER16
+#define LED_BLINK_IRQ        TIMER16_IRQn
+
+/******************************************************************************/
+
+#endif //BOARD_CONFIG_H

inc/fwdgt.h

@@ -0,0 +1,17 @@
+//
+// Created by yelv1 on 24-12-29.
+//
+
+#ifndef FWDGT_H
+#define FWDGT_H
+
+#include "gd32e23x.h"
+#include "board_config.h"
+
+void watchdog_init(void);
+
+void fwdgt_reset_mcu(void);
+
+void watchdog_reload(void);
+
+#endif //FWDGT_H

inc/gd32e23x_it.h

@@ -36,6 +36,9 @@ OF SUCH DAMAGE.
 #define GD32E23X_IT_H
 
 #include "gd32e23x.h"
+#include "main.h"
+#include "systick.h"
+#include "board_config.h"
 
 /* function declarations */
 /* this function handles NMI exception */
@@ -49,4 +52,6 @@ void PendSV_Handler(void);
 /* this function handles SysTick exception */
 void SysTick_Handler(void);
 
+void TIMER16_IRQHandler(void);
+
 #endif /* GD32E23X_IT_H */

inc/i2c.h

@@ -0,0 +1,53 @@
+//
+// Created by dell on 24-12-20.
+//
+
+#ifndef I2C_H
+#define I2C_H
+
+#include "gd32e23x_it.h"
+#include "gd32e23x.h"
+#include "systick.h"
+#include "main.h"
+#include <stdbool.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include "board_config.h"
+
+/******************************************************************************/
+
+#define I2C_SPEED       20000
+
+#define I2C_TIME_OUT    (uint16_t)(5000)
+#define I2C_OK          1
+#define I2C_FAIL        0
+#define I2C_END         1
+
+/******************************************************************************/
+
+typedef enum {
+    I2C_START = 0,
+    I2C_SEND_ADDRESS,
+    I2C_CLEAR_ADDRESS_FLAG,
+    I2C_TRANSMIT_DATA,
+    I2C_STOP
+} i2c_process_enum;
+
+/******************************************************************************/
+
+void i2c_gpio_config(void);
+
+void i2c_config(void);
+
+void i2c_bus_reset(void);
+
+void i2c_scan(void);
+
+uint8_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data[2]);
+
+uint8_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data);
+
+#endif //I2C_H

inc/led.h

@@ -0,0 +1,14 @@
+//
+// Created by yelv1 on 24-12-30.
+//
+
+#ifndef LED_H
+#define LED_H
+
+#include "gd32e23x_it.h"
+#include "gd32e23x.h"
+#include "board_config.h"
+
+void led_blink_config(void);
+
+#endif //LED_H

inc/main.h

@@ -35,4 +35,19 @@ OF SUCH DAMAGE.
 #ifndef MAIN_H
 #define MAIN_H
 
+#include <stdio.h>
+#include "gd32e23x.h"
+#include "systick.h"
+#include "gd32e23x_libopt.h"
+#include "led.h"
+#include "usart.h"
+#include "fwdgt.h"
+#include "board_config.h"
+
+#ifdef SOFTWARE_IIC
+#include "soft_i2c.h"
+#else
+#include "i2c.h"
+#endif
+
 #endif /* MAIN_H */

inc/peripheral.h

@@ -1,11 +0,0 @@
-//
-// Created by yelv1 on 24-9-22.
-//
-
-#ifndef PERIPHERAL_H
-#define PERIPHERAL_H
-
-void usart_config(void);
-void led_blink_config(void);
-
-#endif //PERIPHERAL_H

inc/soft_i2c.h

@@ -0,0 +1,53 @@
+//
+// Created by dell on 24-12-28.
+//
+
+#ifndef SOFT_I2C_H
+#define SOFT_I2C_H
+
+#include "gd32e23x_it.h"
+#include "gd32e23x.h"
+#include "systick.h"
+#include "main.h"
+
+#include "board_config.h"
+
+/******************************************************************************/
+
+#define I2C_SCL_HIGH()      gpio_bit_set(I2C_SCL_PORT, I2C_SCL_PIN)
+#define I2C_SCL_LOW()       gpio_bit_reset(I2C_SCL_PORT, I2C_SCL_PIN)
+#define I2C_SDA_HIGH()      gpio_bit_set(I2C_SDA_PORT, I2C_SDA_PIN)
+#define I2C_SDA_LOW()       gpio_bit_reset(I2C_SDA_PORT, I2C_SDA_PIN)
+#define I2C_SDA_READ()      gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN)
+
+/******************************************************************************/
+
+#define SOFT_I2C_OK          1
+#define SOFT_I2C_FAIL        0
+#define SOFT_I2C_END         1
+
+/******************************************************************************/
+
+void soft_i2c_delay(void);
+
+void soft_i2c_config(void);
+
+void soft_i2c_start(void);
+
+void soft_i2c_stop(void);
+
+void soft_i2c_send_ack(void);
+
+void soft_i2c_send_nack(void);
+
+uint8_t soft_i2c_wait_ack(void);
+
+void soft_i2c_send_byte(uint8_t data);
+
+uint8_t soft_i2c_receive_byte(uint8_t ack);
+
+uint8_t soft_i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data[2]);
+
+uint8_t soft_i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data);
+
+#endif //SOFT_I2C_H

inc/usart.h

@@ -0,0 +1,15 @@
+//
+// Created by yelv1 on 24-12-30.
+//
+
+#ifndef USART_H
+#define USART_H
+
+#include "gd32e23x.h"
+#include "board_config.h"
+
+void usart_config(void);
+
+void rs485_config(void);
+
+#endif //USART_H

src/fwdgt.c

@@ -0,0 +1,47 @@
+//
+// Created by yelv1 on 24-12-29.
+//
+
+#include "fwdgt.h"
+
+/**
+ * @brief  Initialize the watchdog
+ * @param  None
+ * @retval None
+ */
+void watchdog_init(void) {
+    /* Enable the LSI clock */
+    rcu_osci_on(RCU_IRC40K);
+    rcu_osci_stab_wait(RCU_IRC40K);
+
+    /* Configure FWDGT counter clock: 40KHz(IRC40K) / 64 = 0.625 KHz */
+    fwdgt_config(625, FWDGT_PSC_DIV64); // Set timeout to 1 seconds (625 / 0.625 KHz)
+
+    /* Enable FWDGT */
+    fwdgt_enable();
+}
+
+/**
+ * @brief  Reset the MCU
+ * @param  None
+ * @retval None
+ */
+void fwdgt_reset_mcu(void) {
+    /* Enable the write access to the FWDGT_CTL register */
+    FWDGT_CTL = FWDGT_WRITEACCESS_ENABLE;
+
+    /* Configure FWDGT to trigger a system reset */
+    fwdgt_config(50, FWDGT_PSC_DIV4);
+
+    /* Reload the counter to trigger the reset */
+    fwdgt_counter_reload();
+}
+
+/**
+ * @brief  Reload the watchdog counter
+ * @param  None
+ * @retval None
+ */
+void watchdog_reload(void) {
+    fwdgt_counter_reload();
+}

src/gd32e23x_it.c

@@ -33,8 +33,6 @@ OF SUCH DAMAGE.
 */
 
 #include "gd32e23x_it.h"
-#include "main.h"
-#include "systick.h"
 
 /*!
     \brief      this function handles NMI exception
@@ -98,21 +96,27 @@ void SysTick_Handler(void)
 {
 }
 
-void TIMER13_IRQHandler(void)
+/*!
+    \brief      this function handles TIMER16 interrupt request
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void TIMER16_IRQHandler(void)
 {
-    if (timer_interrupt_flag_get(TIMER13, TIMER_INT_FLAG_UP) == SET)
+    if (timer_interrupt_flag_get(LED_BLINK_TIMER, TIMER_INT_FLAG_UP) == SET)
     {
-        timer_interrupt_flag_clear(TIMER13, TIMER_INT_FLAG_UP);
+        timer_interrupt_flag_clear(LED_BLINK_TIMER, TIMER_INT_FLAG_UP);
         static uint8_t led_status = 0;
         if (led_status)
         {
             //! turn on led & reconfig timer13 period to 19000(1900ms)
-            gpio_bit_write(GPIOB, GPIO_PIN_1, RESET);
+            gpio_bit_write(LED_PORT, LED_PIN, RESET);
-            timer_autoreload_value_config(TIMER13, 19200);
+            timer_autoreload_value_config(LED_BLINK_TIMER, 19200);
         } else {
             //! turn off led & reconfig timer13 period to 1000(100ms)
-            gpio_bit_write(GPIOB, GPIO_PIN_1, SET);
+            gpio_bit_write(LED_PORT, LED_PIN, SET);
-            timer_autoreload_value_config(TIMER13, 800);
+            timer_autoreload_value_config(LED_BLINK_TIMER, 800);
         }
         led_status = !led_status;
     }

src/i2c.c

@@ -0,0 +1,476 @@
+//
+// Created by dell on 24-12-20.
+//
+
+#include "i2c.h"
+
+/*!
+    \brief      configure the GPIO ports
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void i2c_gpio_config(void) {
+    /* enable IIC GPIO clock */
+    rcu_periph_clock_enable(I2C_GPIO_RCU);
+
+    /* connect I2C_SCL_PIN to I2C_SCL */
+    gpio_af_set(I2C_SCL_PORT, I2C_GPIO_AF, I2C_SCL_PIN);
+    /* connect I2C_SDA_PIN to I2C_SDA */
+    gpio_af_set(I2C_SDA_PORT, I2C_GPIO_AF, I2C_SDA_PIN);
+    /* configure GPIO pins of I2C */
+    gpio_mode_set(I2C_SCL_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, I2C_SCL_PIN);
+    gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
+    gpio_mode_set(I2C_SDA_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, I2C_SDA_PIN);
+    gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
+}
+
+/*!
+    \brief      configure the I2CX interface
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void i2c_config(void) {
+    /* configure I2C GPIO */
+    i2c_gpio_config();
+    /* enable I2C clock */
+    rcu_periph_clock_enable(I2C_RCU);
+    /* configure I2C clock */
+    i2c_clock_config(I2C_PHY, I2C_SPEED, I2C_DTCY_2);
+    /* configure I2C address */
+    i2c_mode_addr_config(I2C_PHY, I2C_I2CMODE_ENABLE, I2C_ADDFORMAT_7BITS, 0xA0);
+    /* enable I2CX */
+    i2c_enable(I2C_PHY);
+    /* enable acknowledge */
+    i2c_ack_config(I2C_PHY, I2C_ACK_ENABLE);
+}
+
+/*!
+    \brief      reset I2C bus
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void i2c_bus_reset(void) {
+    i2c_deinit(I2C_PHY);
+    /* configure SDA/SCL for GPIO */
+    GPIO_BC(I2C_SCL_PORT) |= I2C_SCL_PIN;
+    GPIO_BC(I2C_SDA_PORT) |= I2C_SDA_PIN;
+    gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
+    gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
+    __NOP();
+    __NOP();
+    __NOP();
+    __NOP();
+    __NOP();
+    GPIO_BOP(I2C_SCL_PORT) |= I2C_SCL_PIN;
+    __NOP();
+    __NOP();
+    __NOP();
+    __NOP();
+    __NOP();
+    GPIO_BOP(I2C_SDA_PORT) |= I2C_SDA_PIN;
+    /* connect I2C_SCL_PIN to I2C_SCL */
+    /* connect I2C_SDA_PIN to I2C_SDA */
+    gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
+    gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
+    /* configure the I2CX interface */
+    i2c_config();
+}
+
+/**
+ * @brief 扫描I2C总线，查找连接的设备
+ *
+ * 该函数会扫描I2C总线上的所有地址（1到126），并尝试与每个地址进行通信。
+ * 如果在某个地址上发现了设备，则会打印出该设备的地址。
+ * 最后会打印出找到的设备总数。
+ */
+void i2c_scan(void) {
+    uint32_t timeout;
+    uint8_t address;
+    int found_devices = 0;
+
+    printf("Scanning I2C bus...\r\n");
+
+    for (address = 1; address < 127; address++) {
+        timeout = 0;
+
+        // 生成起始条件
+        while (i2c_flag_get(I2C_PHY, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT))
+            timeout++;
+        if (timeout >= I2C_TIME_OUT) {
+            continue; // 超时，跳过该地址
+        }
+        i2c_start_on_bus(I2C_PHY);
+        timeout = 0;
+
+        // 等待起始条件发送完成
+        while (!i2c_flag_get(I2C_PHY, I2C_FLAG_SBSEND) && (timeout < I2C_TIME_OUT))
+            timeout++;
+        if (timeout >= I2C_TIME_OUT) {
+            continue; // 超时，跳过该地址
+        }
+        i2c_master_addressing(I2C_PHY, (address << 1), I2C_TRANSMITTER);
+        timeout = 0;
+
+        // 等待地址发送完成
+        while (!i2c_flag_get(I2C_PHY, I2C_FLAG_ADDSEND) && (timeout < I2C_TIME_OUT))
+            timeout++;
+        if (timeout < I2C_TIME_OUT) {
+            i2c_flag_clear(I2C_PHY, I2C_FLAG_ADDSEND);
+            printf("Found device at 0x%02X\r\n", address);
+            found_devices++;
+        }
+
+        // 生成停止条件
+        i2c_stop_on_bus(I2C_PHY);
+
+        timeout = 0;
+
+        while (i2c_flag_get(I2C_PHY, I2C_FLAG_STPDET) && (timeout < I2C_TIME_OUT))
+            timeout++;
+    }
+
+    if (found_devices == 0) {
+        printf("No I2C devices found.\r\n");
+    } else {
+        printf("Total %d I2C devices found.\r\n", found_devices);
+    }
+}
+
+uint8_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data[2]) {
+    uint8_t state = I2C_START;
+    uint16_t timeout = 0;
+    uint8_t i2c_timeout_flag = 0;
+
+    /* enable acknowledge */
+    i2c_ack_config(I2C_PHY, I2C_ACK_ENABLE);
+    while (!(i2c_timeout_flag)) {
+        switch (state) {
+            case I2C_START:
+                /* i2c master sends start signal only when the bus is idle */
+                while (i2c_flag_get(I2C_PHY, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    i2c_start_on_bus(I2C_PHY);
+                    timeout = 0;
+                    state = I2C_SEND_ADDRESS;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c bus is busy in WRITE BYTE!\n");
+#endif
+                }
+                break;
+            case I2C_SEND_ADDRESS:
+                /* i2c master sends START signal successfully */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    i2c_master_addressing(I2C_PHY, slave_addr, I2C_TRANSMITTER);
+                    timeout = 0;
+                    state = I2C_CLEAR_ADDRESS_FLAG;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends start signal timeout in WRITE BYTE!\n");
+#endif
+                }
+                break;
+            case I2C_CLEAR_ADDRESS_FLAG:
+                /* address flag set means i2c slave sends ACK */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_ADDSEND)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    i2c_flag_clear(I2C_PHY, I2C_FLAG_ADDSEND);
+                    timeout = 0;
+                    state = I2C_TRANSMIT_DATA;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master clears address flag timeout in WRITE BYTE!\n");
+#endif
+                }
+                break;
+            case I2C_TRANSMIT_DATA:
+                /* wait until the transmit data buffer is empty */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    /* send IIC register address */
+                    i2c_data_transmit(I2C_PHY, reg_addr);
+                    timeout = 0;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends data timeout in WRITE BYTE!\n");
+#endif
+                }
+
+            /* wait until BTC bit is set */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    /* send register MSB value */
+                    i2c_data_transmit(I2C_PHY, data[0]);
+                    timeout = 0;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends MSB data timeout in WRITE BYTE!\n");
+#endif
+                }
+
+            /* wait until BTC bit is set */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    /* send register LSB value */
+                    i2c_data_transmit(I2C_PHY, data[1]);
+                    timeout = 0;
+                    state = I2C_STOP;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends LSB data timeout in WRITE BYTE!\n");
+#endif
+                }
+
+            /* wait until BTC bit is set */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    state = I2C_STOP;
+                    timeout = 0;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends data timeout in WRITE BYTE!\n");
+#endif
+                }
+                break;
+            case I2C_STOP:
+                /* send a stop condition to I2C bus */
+                i2c_stop_on_bus(I2C_PHY);
+            /* i2c master sends STOP signal successfully */
+                while ((I2C_CTL0(I2C_PHY) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    timeout = 0;
+                    state = I2C_END;
+                    i2c_timeout_flag = I2C_OK;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends stop signal timeout in WRITE BYTE!\n");
+#endif
+                }
+                break;
+            default:
+                state = I2C_START;
+                i2c_timeout_flag = I2C_OK;
+                timeout = 0;
+#ifdef DEBUG_VERBOES
+                printf("i2c master sends start signal in WRITE BYTE.\n");
+#endif
+                break;
+        }
+    }
+    return I2C_END;
+}
+
+uint8_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data) {
+    uint8_t state = I2C_START;
+    uint8_t read_cycle = 0;
+    uint16_t timeout = 0;
+    uint8_t i2c_timeout_flag = 0;
+    uint8_t number_of_byte = 2;
+
+    /* enable acknowledge */
+    i2c_ack_config(I2C_PHY, I2C_ACK_ENABLE);
+
+    while (!(i2c_timeout_flag)) {
+        switch (state) {
+            case I2C_START:
+                if (RESET == read_cycle) {
+                    /* i2c master sends start signal only when the bus is idle */
+                    while (i2c_flag_get(I2C_PHY, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT)) {
+                        timeout++;
+                    }
+                    if (timeout < I2C_TIME_OUT) {
+                        /* whether to send ACK or not for the next byte */
+                        i2c_ackpos_config(I2C_PHY, I2C_ACKPOS_NEXT);
+                    } else {
+                        // i2c_bus_reset();
+                        timeout = 0;
+                        state = I2C_START;
+#ifdef DEBUG_VERBOES
+                        printf("i2c bus is busy in READ!\n");
+#endif
+                    }
+                }
+            /* send the start signal */
+                i2c_start_on_bus(I2C_PHY);
+                timeout = 0;
+                state = I2C_SEND_ADDRESS;
+                break;
+            case I2C_SEND_ADDRESS:
+                /* i2c master sends START signal successfully */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    if (RESET == read_cycle) {
+                        i2c_master_addressing(I2C_PHY, slave_addr, I2C_TRANSMITTER);
+                        state = I2C_CLEAR_ADDRESS_FLAG;
+                    } else {
+                        i2c_master_addressing(I2C_PHY, slave_addr, I2C_RECEIVER);
+                        i2c_ack_config(I2C_PHY, I2C_ACK_DISABLE);
+                        state = I2C_CLEAR_ADDRESS_FLAG;
+                    }
+                    timeout = 0;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+                    read_cycle = RESET;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends start signal timeout in READ!\n");
+#endif
+                }
+                break;
+            case I2C_CLEAR_ADDRESS_FLAG:
+                /* address flag set means i2c slave sends ACK */
+                while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_ADDSEND)) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    i2c_flag_clear(I2C_PHY, I2C_FLAG_ADDSEND);
+                    if ((SET == read_cycle) && (1 == number_of_byte)) {
+                        /* send a stop condition to I2C bus */
+                        i2c_stop_on_bus(I2C_PHY);
+                    }
+                    timeout = 0;
+                    state = I2C_TRANSMIT_DATA;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+                    read_cycle = RESET;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master clears address flag timeout in READ!\n");
+#endif
+                }
+                break;
+            case I2C_TRANSMIT_DATA:
+                if (RESET == read_cycle) {
+                    /* wait until the transmit data buffer is empty */
+                    while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
+                        timeout++;
+                    }
+                    if (timeout < I2C_TIME_OUT) {
+                        /* send the EEPROM's internal address to write to : only one byte address */
+                        i2c_data_transmit(I2C_PHY, reg_addr);
+                        timeout = 0;
+                    } else {
+                        timeout = 0;
+                        state = I2C_START;
+                        read_cycle = RESET;
+#ifdef DEBUG_VERBOES
+                        printf("i2c master wait data buffer is empty timeout in READ!\n");
+#endif
+                    }
+                    /* wait until BTC bit is set */
+                    while ((!i2c_flag_get(I2C_PHY, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
+                        timeout++;
+                    }
+                    if (timeout < I2C_TIME_OUT) {
+                        timeout = 0;
+                        state = I2C_START;
+                        read_cycle = SET;
+                    } else {
+                        timeout = 0;
+                        state = I2C_START;
+                        read_cycle = RESET;
+#ifdef DEBUG_VERBOES
+                        printf("i2c master sends register address timeout in READ!\n");
+#endif
+                    }
+                } else {
+                    while (number_of_byte) {
+                        timeout++;
+                        if (2 == number_of_byte) {
+                            /* wait until BTC bit is set */
+                            while (!i2c_flag_get(I2C_PHY, I2C_FLAG_BTC));
+                            /* send a stop condition to I2C bus */
+                            i2c_stop_on_bus(I2C_PHY);
+                        }
+                        /* wait until RBNE bit is set */
+                        if (i2c_flag_get(I2C_PHY, I2C_FLAG_RBNE)) {
+                            /* read a byte from the EEPROM */
+                            *data = i2c_data_receive(I2C_PHY);
+                            /* point to the next location where the byte read will be saved */
+                            data++;
+                            /* decrement the read bytes counter */
+                            number_of_byte--;
+                            timeout = 0;
+                        }
+                        if (timeout > I2C_TIME_OUT) {
+                            timeout = 0;
+                            state = I2C_START;
+                            read_cycle = 0;
+#ifdef DEBUG_VERBOES
+                            printf("i2c master sends data timeout in READ!\n");
+#endif
+                        }
+                    }
+                    timeout = 0;
+                    state = I2C_STOP;
+                }
+                break;
+            case I2C_STOP:
+                /* i2c master sends STOP signal successfully */
+                while ((I2C_CTL0(I2C_PHY) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
+                    timeout++;
+                }
+                if (timeout < I2C_TIME_OUT) {
+                    timeout = 0;
+                    state = I2C_END;
+                    i2c_timeout_flag = I2C_OK;
+                } else {
+                    timeout = 0;
+                    state = I2C_START;
+                    read_cycle = 0;
+#ifdef DEBUG_VERBOES
+                    printf("i2c master sends stop signal timeout in READ!\n");
+#endif
+                }
+                break;
+            default:
+                state = I2C_START;
+                read_cycle = 0;
+                i2c_timeout_flag = I2C_OK;
+                timeout = 0;
+#ifdef DEBUG_VERBOES
+                printf("i2c master sends start signal in READ.\n");
+#endif
+                break;
+        }
+    }
+    return I2C_END;
+}

src/led.c

@@ -0,0 +1,39 @@
+//
+// Created by yelv1 on 24-12-30.
+//
+
+#include "led.h"
+
+/*!
+    \brief      led blink configuration
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void led_blink_config(void)
+{
+    rcu_periph_clock_enable(LED_RCU);
+
+    gpio_mode_set(LED_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LED_PIN);
+    gpio_output_options_set(LED_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, LED_PIN);
+    gpio_bit_write(LED_PORT, LED_PIN, SET);
+
+    rcu_periph_clock_enable(LED_BLINK_TIMER_RCU);
+    timer_deinit(LED_BLINK_TIMER);
+
+    timer_parameter_struct timer_initpara;
+    timer_struct_para_init(&timer_initpara);
+    timer_initpara.prescaler        =7199;
+    timer_initpara.alignedmode      =TIMER_COUNTER_EDGE;
+    timer_initpara.counterdirection =TIMER_COUNTER_UP;
+    timer_initpara.period           =9999;
+    timer_initpara.clockdivision    =TIMER_CKDIV_DIV1;
+    timer_init(LED_BLINK_TIMER, &timer_initpara);
+
+    timer_auto_reload_shadow_enable(LED_BLINK_TIMER);
+    timer_interrupt_enable(LED_BLINK_TIMER, TIMER_INT_UP);
+
+    timer_enable(LED_BLINK_TIMER);
+
+    nvic_irq_enable(LED_BLINK_IRQ, 2);
+}

src/main.c

@@ -5,12 +5,6 @@
     \version 2024-02-22, V2.1.0, firmware for GD32E23x
 */
 #include "main.h"
-#include <stdio.h>
-#include "gd32e23x.h"
-#include "systick.h"
-#include "gd32e23x_libopt.h"
-
-#include "peripheral.h"
 
 /*!
     \brief      main function
@@ -22,25 +16,28 @@ int main(void)
 {
     /* configure systick */
     systick_config();
-    usart_config();
+    /* configure USART */
+    rs485_config();
+    /* configure LED */
     led_blink_config();
+    /* configure FWDGT */
+    watchdog_init();
 
-    delay_ms(5000);
     printf("system start!\r\n");
 
     while(1){
-    printf("hello world!\r\n");
+        printf("hello world!\r\n");
-    delay_ms(5000);
+        delay_ms(500);
+
+        watchdog_reload();
     }
 }
 
 /* retarget the C library printf function to the USART */
-int _write (int fd, char *pBuffer, int size)
+int _write(int fd, char *pBuffer, int size) {
-{
+    for (int i = 0; i < size; i++) {
-    for (int i = 0; i < size; i++)
+        usart_data_transmit(USART0, (uint8_t) pBuffer[i]);
-    {
+        while (RESET == usart_flag_get(USART0, USART_FLAG_TBE));
-        usart_data_transmit(USART0, (uint8_t)pBuffer[i]);
-        while(RESET == usart_flag_get(USART0, USART_FLAG_TBE));
     }
     return size;
 }

src/peripheral.c

@@ -1,63 +0,0 @@
-//
-// Created by yelv1 on 24-9-22.
-//
-#include "peripheral.h"
-#include "gd32e23x.h"
-
-void usart_config(void)
-{
-    rcu_periph_clock_enable(RCU_GPIOA);
-    rcu_periph_clock_enable(RCU_USART0);
-
-    gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_3);
-    gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_2);
-
-    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_3);
-    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_3);
-    gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_2);
-    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_2);
-
-    usart_deinit(USART0);
-    usart_baudrate_set(USART0, 115200U);
-    usart_receive_config(USART0, USART_RECEIVE_ENABLE);
-    usart_transmit_config(USART0, USART_TRANSMIT_ENABLE);
-
-    usart_enable(USART0);
-
-    gpio_mode_set(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO_PIN_4);
-    gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_4);
-
-    gpio_bit_write(GPIOA, GPIO_PIN_4, SET);
-}
-
-/*!
-    \brief      led blink configuration
-    \param[in]  none
-    \param[out] none
-    \retval     none
-*/
-void led_blink_config(void)
-{
-    rcu_periph_clock_enable(RCU_GPIOB);
-
-    gpio_mode_set(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO_PIN_1);
-    gpio_output_options_set(GPIOB, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, GPIO_PIN_1);
-    gpio_bit_write(GPIOB, GPIO_PIN_1, SET);
-
-    rcu_periph_clock_enable(RCU_TIMER13);
-    timer_deinit(RCU_TIMER13);
-
-    timer_parameter_struct timer_initpara;
-    timer_struct_para_init(&timer_initpara);
-    timer_initpara.prescaler        =7199;
-    timer_initpara.alignedmode      =TIMER_COUNTER_EDGE;
-    timer_initpara.counterdirection =TIMER_COUNTER_UP;
-    timer_initpara.period           =999;
-    timer_initpara.clockdivision    =TIMER_CKDIV_DIV1;
-    timer_init(TIMER13, &timer_initpara);
-
-    timer_auto_reload_shadow_enable(TIMER13);
-    timer_interrupt_enable(TIMER13, TIMER_INT_UP);
-    nvic_irq_enable(TIMER13_IRQn, 0);
-    timer_enable(TIMER13);
-}

src/soft_i2c.c

@@ -0,0 +1,217 @@
+//
+// Created by dell on 24-12-28.
+//
+
+#include "soft_i2c.h"
+
+/*!
+    \brief      delay
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void soft_i2c_delay(void) {
+    delay_us(20); // Adjust delay as needed
+    /* delay to freq
+     *  15KHz: delay_us(20);
+     *  65KHz: delay_us(1);
+     */
+}
+
+/*!
+    \brief      configure the software IIC GPIO
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void soft_i2c_config(void) {
+    rcu_periph_clock_enable(I2C_GPIO_RCU);
+
+    gpio_mode_set(I2C_SCL_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_PULLUP, I2C_SCL_PIN);
+    gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
+
+    gpio_mode_set(I2C_SDA_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_PULLUP, I2C_SDA_PIN);
+    gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
+
+    I2C_SCL_HIGH();
+    I2C_SDA_HIGH();
+}
+
+/*!
+    \brief      generate I2C start signal
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void soft_i2c_start(void) {
+    I2C_SDA_HIGH();
+    I2C_SCL_HIGH();
+    soft_i2c_delay();
+    I2C_SDA_LOW();
+    soft_i2c_delay();
+    I2C_SCL_LOW();
+}
+
+/*!
+    \brief      generate I2C stop signal
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void soft_i2c_stop(void) {
+    // sda_out();
+    I2C_SCL_LOW();
+    I2C_SDA_LOW();
+    soft_i2c_delay();
+    I2C_SCL_HIGH();
+    soft_i2c_delay();
+    I2C_SDA_HIGH();
+}
+
+/*!
+    \brief      send I2C ACK signal
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void soft_i2c_send_ack(void) {
+    // sda_out();
+    I2C_SDA_LOW();
+    soft_i2c_delay();
+    I2C_SCL_HIGH();
+    soft_i2c_delay();
+    I2C_SCL_LOW();
+    soft_i2c_delay();
+    I2C_SDA_HIGH();
+}
+
+/*!
+    \brief      send I2C NACK signal
+    \param[in]  none
+    \param[out] none
+    \retval     none
+*/
+void soft_i2c_send_nack(void) {
+    I2C_SDA_HIGH();
+    soft_i2c_delay();
+    I2C_SCL_HIGH();
+    soft_i2c_delay();
+    I2C_SCL_LOW();
+    soft_i2c_delay();
+    I2C_SDA_HIGH();
+}
+
+/*!
+    \brief      wait I2C ACK signal
+    \param[in]  none
+    \param[out] none
+    \retval     0: ACK received, 1: ACK not received
+*/
+uint8_t soft_i2c_wait_ack(void) {
+    I2C_SDA_HIGH();
+    soft_i2c_delay();
+    I2C_SCL_HIGH();
+    soft_i2c_delay();
+    uint8_t ack = !I2C_SDA_READ();
+    I2C_SCL_LOW();
+    return ack;
+}
+
+/*!
+    \brief      send a byte via I2C
+    \param[in]  byte: byte to be sent
+    \param[out] none
+    \retval     none
+*/
+void soft_i2c_send_byte(uint8_t byte) {
+    // sda_out();
+    for (int i = 0; i < 8; i++) {
+        if (byte & 0x80) {
+            I2C_SDA_HIGH();
+        } else {
+            I2C_SDA_LOW();
+        }
+        byte <<= 1;
+        soft_i2c_delay();
+        I2C_SCL_HIGH();
+        soft_i2c_delay();
+        I2C_SCL_LOW();
+        soft_i2c_delay();
+    }
+}
+
+/*!
+    \brief      receive a byte via I2C
+    \param[in]  ack: 1: send ACK, 0: send NACK
+    \param[out] none
+    \retval     received byte
+*/
+uint8_t soft_i2c_receive_byte(uint8_t ack) {
+    uint8_t byte = 0;
+    I2C_SDA_HIGH();
+    for (int i = 0; i < 8; i++) {
+        byte <<= 1;
+        I2C_SCL_HIGH();
+        soft_i2c_delay();
+        if (I2C_SDA_READ()) {
+            byte |= 0x01;
+        }
+        I2C_SCL_LOW();
+        soft_i2c_delay();
+    }
+    if (ack) {
+        soft_i2c_send_ack();
+    } else {
+        soft_i2c_send_nack();
+    }
+    return byte;
+}
+
+uint8_t soft_i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data[2]) {
+    soft_i2c_start();
+    soft_i2c_send_byte(slave_addr);
+    if (!soft_i2c_wait_ack()) {
+        soft_i2c_stop();
+        return SOFT_I2C_FAIL;
+    }
+    soft_i2c_send_byte(reg_addr);
+    if (!soft_i2c_wait_ack()) {
+        soft_i2c_stop();
+        return SOFT_I2C_FAIL;
+    }
+    soft_i2c_send_byte(data[0]);
+    if (!soft_i2c_wait_ack()) {
+        soft_i2c_stop();
+        return SOFT_I2C_FAIL;
+    }
+    soft_i2c_send_byte(data[1]);
+    if (soft_i2c_wait_ack()){}
+    soft_i2c_stop();
+    return SOFT_I2C_OK;
+}
+
+uint8_t soft_i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data)
+{
+    soft_i2c_start();
+    soft_i2c_send_byte(slave_addr);
+    if (!soft_i2c_wait_ack()) {
+        soft_i2c_stop();
+        return SOFT_I2C_FAIL;
+    }
+    soft_i2c_send_byte(reg_addr);
+    if (!soft_i2c_wait_ack()) {
+        soft_i2c_stop();
+        return SOFT_I2C_FAIL;
+    }
+    soft_i2c_start();
+    soft_i2c_send_byte(slave_addr | 0x01);
+    if (!soft_i2c_wait_ack()) {
+        soft_i2c_stop();
+        return SOFT_I2C_FAIL;
+    }
+    soft_i2c_delay();
+    data[0] = soft_i2c_receive_byte(1);
+    data[1] = soft_i2c_receive_byte(0);
+    soft_i2c_stop();
+    return SOFT_I2C_OK;
+}

src/usart.c

@@ -0,0 +1,46 @@
+//
+// Created by yelv1 on 24-12-30.
+//
+
+#include "usart.h"
+
+/**
+ * @brief  configure the USART
+ * @param  none
+ * @retval none
+ */
+void usart_config(void)
+{
+    rcu_periph_clock_enable(USART_GPIO_RCU);
+    rcu_periph_clock_enable(USART_RCU);
+
+    gpio_af_set(USART_GPIO_PORT, USART_GPIO_AF, USART_RX_PIN);
+    gpio_af_set(USART_GPIO_PORT, USART_GPIO_AF, USART_TX_PIN);
+
+    gpio_mode_set(USART_GPIO_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, USART_RX_PIN);
+    gpio_output_options_set(USART_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, USART_RX_PIN);
+    gpio_mode_set(USART_GPIO_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, USART_TX_PIN);
+    gpio_output_options_set(USART_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, USART_TX_PIN);
+
+    usart_deinit(USART_PHY);
+    usart_baudrate_set(USART_PHY, USART_PHY_BAUDRATE);
+    usart_receive_config(USART_PHY, USART_RECEIVE_ENABLE);
+    usart_transmit_config(USART_PHY, USART_TRANSMIT_ENABLE);
+
+    usart_enable(USART_PHY);
+}
+
+/**
+ * @brief  configure the RS485(MAX13487) driver
+ * @param  none
+ * @retval none
+ */
+void rs485_config(void)
+{
+    usart_config();
+
+    gpio_mode_set(RS485_EN_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, RS485_EN_PIN);
+    gpio_output_options_set(RS485_EN_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, RS485_EN_PIN);
+
+    gpio_bit_write(RS485_EN_PORT, RS485_EN_PIN, SET); //auto dircetion control
+}