stm32 接收蓝牙（uart）等设备命令的处理

方法有两种：

方法1：查询法

static void BT_RX_Handler(void)

{

u8 data = USART_ReceiveData(USART2);

if((BT_Buf_Status & 0x80) == 0)  /* not complete */ 

{

if(BT_Buf_Status & 0x40)

{

BT_RcvBuf[BT_RecCur] = data;

BT_RecCur++;

if((data == 0xEC) && (8 == BT_RecCur))

//if((data == 0xEC))

{

BT_Buf_Status |= (1 << 7);       /* complete */

BT_Handler();

BT_Buf_Status &= ~(1 << 7);       /* clear */

BT_RecCur = 0;

}

}

else

{

/* filt the head */ 

if(data == 0xBC)

{

/* standard cmd */

BT_RcvBuf[BT_RecCur] = data;           /* save the head */

BT_RecCur++;

BT_Buf_Status |= (1 << 6) ;

}

else

{

BT_Buf_Status = 0;

/* not standard cmd, just save */

buff[cnt] = data;

cnt++;

cnt &= (16 - 1);

}

}

}

}

方法二：中断 + FIFO方法

定义结构：

#define MAX_BT_DATA 32

typedef struct _bt_data

{

u8 pBtData[MAX_BT_DATA];

u8 cursor;

}BT_DATA;

static BT_DATA btData;

void BT_Routine(void)

{

u8 cnt = 0;

BT_DATA *pData = &btData;

u8 i = pData->cursor;

u8 count;

if(bt_mode == BT_MODE_NORMAL)

{

count = BT_Rx(pData->pBtData + i, 1);

if(1 == count)

{

//debug("%x ", pData->pBtData[i]);

if(pData->pBtData[i] == 0xBC)

{

cnt = BT_Rx(BT_RcvBuf, 7);

if((cnt == 7) && (BT_RcvBuf[6] == 0xEC) && (BT_RcvBuf[0] == 0x08))

{

//BT_Handler();

//debug("excute the BT-handler .rn");

u8 cmd = BT_RcvBuf[1];

if(BT_GetCmd(cmd))

{

//debug("got the cmd & excute handler .rn");

bt_cmd.bt_handler(BT_RcvBuf[2], BT_RcvBuf[3]);

}

}

else

{

debug("not standard cmd . please retry . rn");

/*

* TODO : here will check package-lost or package-error

*/

u8 i;

for(i = 0; i < cnt ; i++)

{

debug("%x ", BT_RcvBuf[i]);

}

}

}

else if(pData->pBtData[i] == 0x2B)                    /* disconnect */

{

/*

* read the other byte and discard

* @2B 44 69 73 63 6F 6E 6E 65 63 74 0D 0A

*/

cnt = BT_Rx(BT_RcvBuf, 12);

if((12 == cnt ) && (BT_RcvBuf[0] == 'D'))

{

debug("disconnect .rn");

/*

* disconnect ,and switch the mode for connection

*/ 

bt_mode = BT_MODE_ADMIN;

}

}

else

{

/* read and discard */ 

BT_Rx(BT_RcvBuf, 1);

}

}

}

else if(bt_mode == BT_MODE_ADMIN)

{

/*

* get admin package,such as connect and AT cmd

*/ 

count = BT_Rx(pData->pBtData + i, 1);

if(1 == count)

{

if(pData->pBtData[i] == 0x2B) 

{

cnt = BT_Rx(BT_RcvBuf, 1);

if((1 == cnt) && (BT_RcvBuf[0] == 'c'))

{

/*

* read the other byte and discard

* @2B 63 6F 6E 6E 65 63 74 0D 0A 

*/

cnt = BT_Rx(BT_RcvBuf, 8);

debug("connect .rn");

/* switch the mode to normal */ 

bt_mode = BT_MODE_NORMAL;

}

if((1 == cnt) && (BT_RcvBuf[0] == 'o'))

{

debug("OK .rn");

}

}

else

{

/* read and discard */ 

BT_Rx(BT_RcvBuf, 1);

printf("%x ", BT_RcvBuf[0]);

}

}

}

else if(bt_mode == BT_MODE_LOAD)

{

//TODO: load music package

}

}

对于支持“透传+ AT指令”模式的传输设备，且默认是透传模式， 可以定义如下模式：

typedef enum

{

    BT_MODE_NORMAL = 0,          /* normal command mode */ 

    BT_MODE_ADMIN,               /* control mode ,such as AT  */

}BT_MODE;   

当检测到设备disconnect后，切换模式到AT指令模式，这样在透传模式下可以控制输出“AT指令”查询设备信息

更新：

BUG： 以上FIFO接收蓝牙信息时会出现数据丢失的情况；原因是使用RX中断导致中断频率很高。而使用RTOS过程中，许多临界数据需要关中断来保护，所以会出现丢包；

解决：不适用USART的RXNE中断， 而使用idle中断和DMA中断， 这样会大大降低中断频率。

重点代码如下：

初始化USART2 的RX DMA功能：

void HAL_DMA_Init(void)

{

DMA_InitTypeDef DMA_InitStructure;

NVIC_InitTypeDef NVIC_InitStruct;

DMA_RecvBuf = (u8 *)_MemMalloc(DMA_RX_SIZE);         /* never free */

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

DMA_DeInit(DMA_CH);

DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART2->DR;  

DMA_InitStructure.DMA_MemoryBaseAddr = (u32)DMA_RecvBuf;       /* dest addr */

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;             /* periph to buffer */

DMA_InitStructure.DMA_BufferSize = DMA_RX_SIZE;                /* DMA buff 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 buff auto update */

DMA_InitStructure.DMA_Priority = DMA_Priority_High;       /* priority of medium */

DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;                /* not buffer to buffer */

DMA_Init(DMA_CH, &DMA_InitStructure);

/*  transfer complete interrupt */

    NVIC_InitStruct.NVIC_IRQChannel = DMA1_Channel6_IRQn;

    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 1;

    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 3;

    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;

    NVIC_Init(&NVIC_InitStruct);

DMA_ITConfig(DMA_CH,DMA_IT_TC,ENABLE);

DMA_Cmd(DMA_CH, ENABLE);

}

改变DMA BUFF的API：

void DMA_Enable(void)

{ 

DMA_Cmd(DMA_CH, DISABLE ); 

  DMA_SetCurrDataCounter(DMA_CH , DMA_RX_SIZE);   /* DMA buffer */

  DMA_Cmd(DMA_CH, ENABLE);  

}

相关全局变量和宏：

/*

* USART2 RX DMA1 ch6 

*

*/

#define DMA_DEV DMA1

#define DMA_CH DMA1_Channel6

#define DMA_RX_SIZE 4096

static u8 *DMA_RecvBuf;

//static u32 validLength;

最后使能：

USART_DMACmd(USART2 , USART_DMAReq_Rx , ENABLE);      /* enable RX-DMA */

此外， 注释掉原来USART的RXNE中断，加上IDLE相关的中断使能：

// config the interrupt

//USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);    /* RX not empty */ 

USART_ITConfig(USART2, USART_IT_IDLE, ENABLE);      /* IDLE */

最后看中断处理函数里面，其实移植RX中断里面代码即可：

static void BT_IDLE_Handler(void)

{

u32 temp = 0; 

    u16 cnt = 0; 

    u16 i = 0;  

u32 tail = BTRxTail;

u32 space = CIRC_SPACE(BTRxHead,tail,MAX_BT_RX_LEN);

temp = USART2->SR;  

    temp = USART2->DR; //清USART_IT_IDLE标志 

DMA_Cmd(DMA1_Channel6,DISABLE);  

temp = DMA_RX_SIZE - DMA_GetCurrDataCounter(DMA1_Channel6);  

printf("DMA receive : %d rn", temp);

if((space > 0) && (temp > 0))

{

        if(temp >= space)

            cnt = space ;

        else

            cnt = temp;

for(i = 0; i < temp; i++)

{

BTRxBuf[tail++] = DMA_RecvBuf[i];  

BTRxTail = tail & (MAX_BT_RX_LEN - 1);

}

}

else

{

// should not happen

debug("BT_RX_Handler RxBuf over flow .rn");

}

DMA_SetCurrDataCounter(DMA1_Channel6,DMA_RX_SIZE);  

DMA_Cmd(DMA1_Channel6,ENABLE);

}