【经验分享】STM32F7xx —— 串口通信

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STMCU小助手发布时间：2021-12-12 21:37

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文章简介:	STM32F7xx —— 串口通信

一、串口初始化过程
1、时钟使能；

2、GPIO初始化；

3、串口波特率设置；

4、串口控制；

5、数据发送与接收

二、几个重要的串口函数

HAL_StatusTypeDef HAL_UART_Init(UART_HandleTypeDef *huart); // 串口初始化
HAL_StatusTypeDef HAL_UART_Transmit(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout); // 串口发送
HAL_StatusTypeDef HAL_UART_Receive(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout); // 串口接收
__HAL_UART_ENABLE_IT(__HANDLE__, __INTERRUPT__) // 串口中断使能
void HAL_NVIC_SetPriority(IRQn_Type IRQn, uint32_t PreemptPriority, uint32_t SubPriority); // 设置中断优先级
void HAL_NVIC_EnableIRQ(IRQn_Type IRQn); // 使能中断

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三、几个重要的结构

// 串口初始化结构体包含了串口句柄波特率配置发送接收缓存 dma等
// 我们只描述前两个基本功能，对效率要求极高可以使用DMA。
typedef struct
{
USART_TypeDef *Instance; /*!< UART registers base address */
UART_InitTypeDef Init; /*!< UART communication parameters */
UART_AdvFeatureInitTypeDef AdvancedInit; /*!< UART Advanced Features initialization parameters */
uint8_t *pTxBuffPtr; /*!< Pointer to UART Tx transfer Buffer */
uint16_t TxXferSize; /*!< UART Tx Transfer size */
uint16_t TxXferCount; /*!< UART Tx Transfer Counter */
uint8_t *pRxBuffPtr; /*!< Pointer to UART Rx transfer Buffer */
uint16_t RxXferSize; /*!< UART Rx Transfer size */
uint16_t RxXferCount; /*!< UART Rx Transfer Counter */
uint16_t Mask; /*!< UART Rx RDR register mask */
DMA_HandleTypeDef *hdmatx; /*!< UART Tx DMA Handle parameters */
DMA_HandleTypeDef *hdmarx; /*!< UART Rx DMA Handle parameters */
HAL_LockTypeDef Lock; /*!< Locking object */
__IO HAL_UART_StateTypeDef gState; /*!< UART state information related to global Handle management
and also related to Tx operations.
This parameter can be a value of @ref HAL_UART_StateTypeDef */
__IO HAL_UART_StateTypeDef RxState; /*!< UART state information related to Rx operations.
This parameter can be a value of @ref HAL_UART_StateTypeDef */
__IO uint32_t ErrorCode; /*!< UART Error code */
}UART_HandleTypeDef;

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// 串口的操作句柄如 USART1 USART2 USART3等
typedef struct
{
__IO uint32_t CR1; /*!< USART Control register 1, Address offset: 0x00 */
__IO uint32_t CR2; /*!< USART Control register 2, Address offset: 0x04 */
__IO uint32_t CR3; /*!< USART Control register 3, Address offset: 0x08 */
__IO uint32_t BRR; /*!< USART Baud rate register, Address offset: 0x0C */
__IO uint32_t GTPR; /*!< USART Guard time and prescaler register, Address offset: 0x10 */
__IO uint32_t RTOR; /*!< USART Receiver Time Out register, Address offset: 0x14 */
__IO uint32_t RQR; /*!< USART Request register, Address offset: 0x18 */
__IO uint32_t ISR; /*!< USART Interrupt and status register, Address offset: 0x1C */
__IO uint32_t ICR; /*!< USART Interrupt flag Clear register, Address offset: 0x20 */
__IO uint32_t RDR; /*!< USART Receive Data register, Address offset: 0x24 */
__IO uint32_t TDR; /*!< USART Transmit Data register, Address offset: 0x28 */
} USART_TypeDef;

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// 设置串口的各个参数波特率字长停止位奇偶校验收发模式硬件流过采样
// 字长：8位/9位
// 停止位：1位/2位
typedef struct
{
uint32_t BaudRate; /*!< This member configures the UART communication baud rate.
The baud rate register is computed using the following formula:
- If oversampling is 16 or in LIN mode,
Baud Rate Register = ((PCLKx) / ((huart->Init.BaudRate)))
- If oversampling is 8,
Baud Rate Register[15:4] = ((2 * PCLKx) / ((huart->Init.BaudRate)))[15:4]
Baud Rate Register[3] = 0
Baud Rate Register[2:0] = (((2 * PCLKx) / ((huart->Init.BaudRate)))[3:0]) >> 1 */
uint32_t WordLength; /*!< Specifies the number of data bits transmitted or received in a frame.
This parameter can be a value of @ref UARTEx_Word_Length */
uint32_t StopBits; /*!< Specifies the number of stop bits transmitted.
This parameter can be a value of @ref UART_Stop_Bits */
uint32_t Parity; /*!< Specifies the parity mode.
This parameter can be a value of @ref UART_Parity
@note When parity is enabled, the computed parity is inserted
at the MSB position of the transmitted data (9th bit when
the word length is set to 9 data bits; 8th bit when the
word length is set to 8 data bits). */
uint32_t Mode; /*!< Specifies whether the Receive or Transmit mode is enabled or disabled.
This parameter can be a value of @ref UART_Mode */
uint32_t HwFlowCtl; /*!< Specifies whether the hardware flow control mode is enabled
or disabled.
This parameter can be a value of @ref UART_Hardware_Flow_Control */
uint32_t OverSampling; /*!< Specifies whether the Over sampling 8 is enabled or disabled, to achieve higher speed (up to fPCLK/8).
This parameter can be a value of @ref UART_Over_Sampling */
uint32_t OneBitSampling; /*!< Specifies whether a single sample or three samples' majority vote is selected.
Selecting the single sample method increases the receiver tolerance to clock
deviations. This parameter can be a value of @ref UART_OneBit_Sampling */
}UART_InitTypeDef;

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四、基本接口设计
我们使用中断接收，普通发送。中断接收到的数据放入队列中，在外部可配置每路串口的功能。

// 抽象出一个串口设备结构体
typedef struct
{
UART_HandleTypeDef handle; // 串口句柄
uart_queue_t recv; // 接收队列
uart_queue_t send; // 发送队列
uint8_t ret; // 接收的值
} uart_dev_t;
static uart_dev_t uart1_dev;
static uart_dev_t uart2_dev;

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// 对外只有通道不再包含USART1...
typedef enum
{
UART_CHANNEL_NONE,
UART_CHANNEL_1,
UART_CHANNEL_2,
UART_CHANNEL_NUM
} uart_channel_t;
// 宏定义串口的基本信息之所以这样写，方便移植修改
#define UART1_CHANNEL USART1
#define UART1_PREEMPT_PRIO UART1_PRIORITY
#define UART1_IRQ USART1_IRQn
#define UART1_IRQ_FUNC USART1_IRQHandler
#define UART1_CLK_ENABLE() __HAL_RCC_USART1_CLK_ENABLE()
#define UART1_TX_PORT GPIOA
#define UART1_TX_PIN GPIO_PIN_10
#define UART1_TX_AF GPIO_AF7_USART1
#define UART1_TX_CONFIG() GPIOConfigExt(UART1_TX_PORT, UART1_TX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, UART1_TX_AF)
#define UART1_RX_PORT GPIOA
#define UART1_RX_PIN GPIO_PIN_9
#define UART1_RX_AF GPIO_AF7_USART1
#define UART1_RX_CONFIG() GPIOConfigExt(UART1_RX_PORT, UART1_RX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, UART1_RX_AF)
#define UART2_CHANNEL USART2
#define UART2_PREEMPT_PRIO UART2_PRIORITY
#define UART2_IRQ USART2_IRQn
#define UART2_IRQ_FUNC USART2_IRQHandler
#define UART2_CLK_ENABLE() __HAL_RCC_USART2_CLK_ENABLE()
#define UART2_TX_PORT GPIOA
#define UART2_TX_PIN GPIO_PIN_2
#define UART2_TX_AF GPIO_AF7_USART2
#define UART2_TX_CONFIG() GPIOConfigExt(UART2_TX_PORT, UART2_TX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, UART2_TX_AF)
#define UART2_RX_PORT GPIOA
#define UART2_RX_PIN GPIO_PIN_3
#define UART2_RX_AF GPIO_AF7_USART2
#define UART2_RX_CONFIG() GPIOConfigExt(UART2_RX_PORT, UART2_RX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, UART2_RX_AF)

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// 串口的基本操作
// 串口1
static void uart1_var_init(void)
{
uart1_dev.recv = uart1_queue_recv;
uart1_dev.send = uart1_queue_send;
UartQueueInit(&uart1_dev.recv);
UartQueueInit(&uart1_dev.send);
}
static void uart1_gpio_init(void)
{
UART1_RX_CONFIG();
UART1_TX_CONFIG();
}
static void uart1_mode_init(uint32_t bound)
{
UART1_CLK_ENABLE();
uart1_dev.handle.Instance = UART1_CHANNEL;
uart1_dev.handle.Init.BaudRate = bound; // 波特率
uart1_dev.handle.Init.WordLength = UART_WORDLENGTH_8B; // 字长为8位数据格式
uart1_dev.handle.Init.StopBits = UART_STOPBITS_1; // 一个停止位
uart1_dev.handle.Init.Parity = UART_PARITY_NONE; // 无奇偶校验位
uart1_dev.handle.Init.HwFlowCtl = UART_HWCONTROL_NONE; // 无硬件流控
uart1_dev.handle.Init.Mode = UART_MODE_TX_RX; // 收发模式
HAL_UART_Init(&uart1_dev.handle); // HAL_UART_Init()会使能UART1
}
static void uart1_nvic_init(void)
{
HAL_NVIC_SetPriority(UART1_IRQ, UART1_PREEMPT_PRIO, 3);
HAL_NVIC_EnableIRQ(UART1_IRQ);
__HAL_UART_ENABLE_IT(&uart1_dev.handle, UART_IT_RXNE);
}
// 串口2
static void uart2_var_init(void)
{
uart2_dev.recv = uart2_queue_recv;
uart2_dev.send = uart2_queue_send;
UartQueueInit(&uart2_dev.recv);
UartQueueInit(&uart2_dev.send);
}
static void uart2_gpio_init(void)
{
UART2_RX_CONFIG();
UART2_TX_CONFIG();
}
static void uart2_mode_init(uint32_t bound)
{
UART2_CLK_ENABLE();
uart2_dev.handle.Instance = UART2_CHANNEL;
uart2_dev.handle.Init.BaudRate = bound;
uart2_dev.handle.Init.WordLength = UART_WORDLENGTH_8B;
uart2_dev.handle.Init.StopBits = UART_STOPBITS_1;
uart2_dev.handle.Init.Parity = UART_PARITY_NONE;
uart2_dev.handle.Init.HwFlowCtl = UART_HWCONTROL_NONE;
uart2_dev.handle.Init.Mode = UART_MODE_TX_RX;
HAL_UART_Init(&uart2_dev.handle);
}
static void uart2_nvic_init(void)
{
HAL_NVIC_EnableIRQ(UART2_IRQ);
HAL_NVIC_SetPriority(UART2_IRQ, UART2_PREEMPT_PRIO, 1);
__HAL_UART_ENABLE_IT(&uart2_dev.handle, UART_IT_RXNE);
}

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// 抽象出一个初始化的结构体每个串口都有的操作
// 定义一个串口的列表
// 下面的函数就是扫描列表到这里为止，这些接口都是给内部使用的，外部文件用不到。
typedef struct
{
uint8_t channel;
uart_dev_t *dev;
void (* var_init_cb)(void);
void (* gpio_init_cb)(void);
void (* mode_init_cb)(uint32_t bound);
void (* nvic_init_cb)(void);
} uart_config_t;
static const uart_config_t uart_configs[] =
{
{UART_CHANNEL_1, &uart1_dev, uart1_var_init, uart1_gpio_init, uart1_mode_init, uart1_nvic_init},
{UART_CHANNEL_2, &uart2_dev, uart2_var_init, uart2_gpio_init, uart2_mode_init, uart2_nvic_init},
};
static uart_dev_t *uart_dev_get(uint8_t channel)
{
uint8_t i;
for(i = 0; i < ARRAY_SIZE(uart_configs); ++i)
{
if(uart_configs.channel == channel)
{
return uart_configs.dev;
}
}
return 0;
}
static void uart_var_init(uint8_t channel)
{
uint8_t i;
for(i = 0; i < ARRAY_SIZE(uart_configs); ++i)
{
if(uart_configs.channel == channel)
{
uart_configs.var_init_cb();
break;
}
}
}
static void uart_gpio_init(uint8_t channel)
{
uint8_t i;
for(i = 0; i < ARRAY_SIZE(uart_configs); ++i)
{
if(uart_configs.channel == channel)
{
uart_configs.gpio_init_cb();
break;
}
}
}
static void uart_mode_init(uint8_t channel, uint32_t bound)
{
uint8_t i;
for(i = 0; i < ARRAY_SIZE(uart_configs); ++i)
{
if(uart_configs.channel == channel)
{
uart_configs.mode_init_cb(bound);
break;
}
}
}
static void uart_nvic_init(uint8_t channel)
{
uint8_t i;
for(i = 0; i < ARRAY_SIZE(uart_configs); ++i)
{
if(uart_configs.channel == channel)
{
uart_configs.nvic_init_cb();
break;
}
}
}