为外设初始化加入注释

app/inc/hardware.h

@@ -1,8 +1,9 @@
 #ifndef __HARDWARE_H
 #define __HARDWARE_H
 
-
+/*接收数组大小*/
 #define MODBUS_RX_BUF_SIZE  256
+/*modbus通信波特率*/
 #define MODBUS_USART_BAUDRATE 19200
 
 

app/src/hardware.c

@@ -1,7 +1,9 @@
 #include "stm32f4xx.h"
 #include "hardware.h"
 
+/*接收数组*/
 uint8_t ModbusRxBuf[MODBUS_RX_BUF_SIZE];
+/*接收数据长度*/
 uint16_t ModbusRxLen = 0;
 
 void ModbusGpioInit(void)
@@ -9,32 +11,37 @@ void ModbusGpioInit(void)
     GPIO_InitTypeDef GPIO_InitStructure;
     
     RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
-    
+
+    /* PA9->USART1_TX，PA10->USART1_RX */
     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
     GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
-    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
+    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;          /*推挽输出*/
     GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
     GPIO_Init(GPIOA, &GPIO_InitStructure);
-    
+
+    /*复用初始化*/
     GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1);
     GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_USART1);
 }
 
+/*硬件有自动收发转换芯片，软件实现modbus只需要当成普通的全双工串口使用即可*/
 void ModbusUsartInit(void)
 {
     USART_InitTypeDef USART_InitStructure;
 
     RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
-  
-    USART_InitStructure.USART_BaudRate = MODBUS_USART_BAUDRATE;
-    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
-    USART_InitStructure.USART_StopBits = USART_StopBits_1;
-    USART_InitStructure.USART_Parity = USART_Parity_No; 
-    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
-    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
+
+    USART_InitStructure.USART_BaudRate = MODBUS_USART_BAUDRATE;         /*配置波特率*/
+    USART_InitStructure.USART_WordLength = USART_WordLength_8b;         /*数据帧长度8字节*/
+    USART_InitStructure.USART_StopBits = USART_StopBits_1;              /*1位停止位*/
+    USART_InitStructure.USART_Parity = USART_Parity_No;                 /*无奇偶校验位，使用crc校验*/
+    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;     /*不使用硬件流控*/
+    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;     /*发送接收全双工*/
     USART_Init(USART1, &USART_InitStructure);
 
+    /*使能串口空闲中断（IDLE）*/
+    /*当RX线路在接收过至少一个字节后，持续一个完整字符时间没有再收到数据，USART会置位IDLE标志并产生中断*/
     USART_ITConfig(USART1, USART_IT_IDLE, ENABLE);
     USART_Cmd(USART1, ENABLE);
 }
@@ -45,34 +52,35 @@ void ModbusDmaInit(void)
 
     RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);
 
-    /* DMA2_Stream2 用于 USART1_RX */
-    DMA_DeInit(DMA2_Stream2);
-    DMA_InitStructure.DMA_Channel = DMA_Channel_4;
-    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(USART1->DR);
-    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)ModbusRxBuf;
-    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
-    DMA_InitStructure.DMA_BufferSize = MODBUS_RX_BUF_SIZE;
-    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
-    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
-    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
-    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
-    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
-    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
-    DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
-    DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_1QuarterFull;
-    DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
-    DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
+    /* DMA2_Stream2_Channel_4 用于 USART1_RX */
+    DMA_DeInit(DMA2_Stream2);                           /*恢复默认状态*/
+    DMA_InitStructure.DMA_Channel = DMA_Channel_4;      /*配置通道4*/
+    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(USART1->DR);     /*设置DMA外设端地址为USART1数据寄存器地址*/
+    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)ModbusRxBuf;          /*设置DMA存储器目标地址为接收缓冲区首地址*/
+    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;                 /*传输方向为外设->内存*/
+    DMA_InitStructure.DMA_BufferSize = MODBUS_RX_BUF_SIZE;                  /*传输最大字节数*/
+    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;        /*禁止外设地址递增*/
+    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;                 /*使能内存地址自增*/
+    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; /*设置外设数据宽度为1字节（8位）*/
+    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;         /*设置内存数据宽度为1字节（8位）*/
+    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;                           /*modbus帧长度不固定，无法使用循环模式，配置为普通模式，每次传输完软件重新使能*/
+    DMA_InitStructure.DMA_Priority = DMA_Priority_High;                     /*高优先级*/
+    DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;                  /*不使用FIFO模式*/
+    DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_1QuarterFull;   /*禁止FIFO后无用*/
+    DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;             /*内存侧单次传输，每次搬运一个数据单位*/
+    DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;     /*外设侧单次传输，每次搬运一个数据单位*/
     DMA_Init(DMA2_Stream2, &DMA_InitStructure);
 
-    /* DMA2_Stream7 用于 USART1_TX */
-    DMA_DeInit(DMA2_Stream7);
-    DMA_InitStructure.DMA_Channel = DMA_Channel_4;
-    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(USART1->DR);
-    DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
+    /* DMA2_Stream7_Channel_4 用于 USART1_TX */
+    /*USART1_TX的其他配置在USART中断中配置*/
+    DMA_DeInit(DMA2_Stream7);                                                                                          
+    DMA_InitStructure.DMA_Channel = DMA_Channel_4;                          
+    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(USART1->DR);     /*设置DMA外设端地址为USART1数据寄存器地址*/
+    DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;                 /*传输方向为内存->外设*/
     DMA_Init(DMA2_Stream7, &DMA_InitStructure);
 
     /* 使能USART的DMA请求 */
-    USART_DMACmd(USART1, USART_DMAReq_Rx | USART_DMAReq_Tx, ENABLE);
+    USART_DMACmd(USART1, USART_DMAReq_Rx | USART_DMAReq_Tx, ENABLE);        /*使能USART1的RX、TX的DMA请求*/
     DMA_Cmd(DMA2_Stream2, ENABLE);
 }
 
@@ -80,9 +88,9 @@ void ModbusNvicInit(void)
 {
     NVIC_InitTypeDef NVIC_InitStructure;
 
-    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
-    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 5; 
-    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
+    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;               
+    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 5;       /*抢占优先级5*/
+    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;              /*响应优先级0*/
     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&NVIC_InitStructure);
 }
@@ -90,6 +98,9 @@ void ModbusNvicInit(void)
 
 void MdobusHardwareInit(void)
 {
+    /*NVIC分组配置*/
+    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4); /*4位抢占优先级，0位子优先级*/
+
     ModbusGpioInit();
     ModbusUsartInit();
     ModbusDmaInit();