NB-IOT开发|nbiot开发教程《二》AT指令类模组驱动-STM32串口实现接收不定长度数据
嵌入式开发中我们要时刻保持代码的高效与整洁一、前言
嵌入式开发中我们要时刻保持代码的高效与整洁。上一节中AT指令模组状态机的实现需要串口实现接收不定长度数据，本文就是说明具体实现方式。
二、原理
串口实现接收不定长度数据原理:串口接收中断接收数据，每次中断时启动数据超时定时器(软件定时器)，每次接收到数据更新定时器时间并将数据压到环形缓冲区中，时间可以为10ms，当定时器超时时即认为接收到完整包。
本次串口驱动的封装是基于cola_os下完成的，关于cola_os的详细介绍可以参考文章:
1.嵌入式开发--300行代码实现操作系统cola_os
2. 嵌入式开发--实现应用层和硬件层分层管理
3.嵌入式开发--STM32上实现驱动注册initcall机制(类linux)
4.嵌入式开发|高效缓冲器设计（C语言）
三、源代码
初始化串口并且初始化串口接收中断
static void uart1_gpio_init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
static void uart1_init(uint32_t bund)
{
USART_InitTypeDef USART_InitStructure;
USART_InitStructure.USART_BaudRate = bund;
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_Init(USART1, &USART_InitStructure);
USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
USART_Cmd(USART1, ENABLE);
USART_ClearFlag(USART1,USART_FLAG_RXNE);
}
static void uart1_nvic_init(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}编写串口驱动功能函数
static int uart1_write(cola_device_t *dev, int pos, const void *buffer, int size)
{
uart1_sendnbyte((uint8_t *)buffer,size);
return size;
}
static int uart1_read(cola_device_t *dev, int pos, void *buffer, int size)
{
return cola_fifo_read(&uart_fifo,buffer,size);
}
static int uart1_config(cola_device_t *dev, void *args, void *var)
{
struct serial_configure *cfg = (struct serial_configure *)args;
if(cfg)
{
uart1_init(cfg->baud_rate);
}
return 0;
}
static struct cola_device_ops uart1_ops =
{
.write = uart1_write,
.read = uart1_read,
.config = uart1_config,
};
串口接收中断：接收中断发生，重启定时器，将数据放到环形缓冲区中
void USART1_IRQHandler(void)
{
uint8_t c;
if((USART1->SR & USART_FLAG_RXNE) == USART_FLAG_RXNE)
{
c = (uint8_t)(USART1->DR);
if(uart1_dev.owner)
{
if(uart1_write_slot( &c, 1))
{
cola_timer_start(&uart_timer,TIMER_ONE_SHOT,pdMS_TO_TICKS(20));
}
}
}
}
初始化软件定时器；
static void uart_timer_cb(uint32_t event)
{
if(uart1_dev.owner)
{
cola_set_event(uart1_dev.owner,SIG_DATA);
}
}
初始化：
void board_setup_usart(void)
{
#ifdef USING_UART1
uart1_configuration(115200);
cola_fifo_init(&uart_fifo,uart_buf,sizeof(uart_buf));
cola_timer_create(&uart_timer,uart_timer_cb);
uart1_dev.name = "uart1";
uart1_dev.dops = &uart1_ops;
cola_device_register(&uart1_dev);
#endif
}四、应用层调用与调试
/******************************** cola os *********************************
* @file : app_uart.c
* @author : sunny.Bit(QQ 1506564994)
Email:[email protected]
* @brief : cola os
******************************************************************************/
#include "config.h"
#include
#include "app.h"
#include "cola_device.h"
#include "cola_os.h"
static task_t uart_task;
static cola_device_t *uart_dev;
static uint8_t tmp[128] = {0};
static void uart_task_cb(uint32_t event)
{
int err = 0;
if(event&SIG_DATA)
{
err = cola_device_read(uart_dev,0,tmp,sizeof(tmp));
if(err)
{
os_log("UART-RX:%d:",err);
cola_device_write(uart_dev,0,tmp,err);
os_log("\r\n");
}
}
}
static void uart_dev_init(void)
{
uart_dev = cola_device_find("uart1");
assert(uart_dev);
cola_device_set_owner(uart_dev,&uart_task);
struct serial_configure cfg;
cfg.baud_rate = 115200;
cola_device_cfg(uart_dev,&cfg,0);
}
void uart_task_init(void)
{
uart_dev_init();
cola_task_create(&uart_task,uart_task_cb);
}
调试:
这样实现是不是很简单。
五、代码下载
https://github.com/sckuck-bit/nb-iot