A simple serial receive (with protocol)

A simple serial receive (with protocol)

Data header information (5)
the data length information (a)
data (<1024)
data check (1)
Data Tail

I. receiving serial data buf

typedef struct _UartCommadType
{
	uint8_t Buffer[1024];	

    uint16_t Index; // buffer index

    uint16_t u8Len;

}UartCommadType;

Two serial port received state, if the reception is not completed within the time limit, the received error

uint16_t g_Uart2CheckTick;//时间限制
uint8_t  g_bUart2Detected;//检测标志

void Uart2_1ms_ISR(void)
{
    if (g_Uart2CheckTick)
    {
        --g_Uart2CheckTick;
        if ( g_Uart2CheckTick == 0 )
        {
            g_bUart2Detected = 0;
            g_Uart2Command.Index = 0;
        }
    }
}

III. Detecting receiver, the data has been put into buf, if the length of data bits is detected, then the received data length in the data length bits End

#define UART_RX_HEADER            ( 0x00 )
#define UART_RX_ID                ( 0x01 )
#define UART_RX_CATEGORY          ( 0x02 )
#define UART_RX_PAGE              ( 0x03 )
#define UART_RX_FUNC              ( 0x04 )
#define UART_RX_DATA_LENGTH       ( 0x05 )
#define UART_RX_CONTROL           ( 0x06 )

void Uart2_RecvHandler(int c)
{
    g_Uart2CheckTick = 50;// time-out control ms

	if((g_Uart2Command.u8CmdLen != 0)&&( g_Uart2Command.Index < g_Uart2Command.u8CmdLen))
	{
		g_Uart2Command.u8CmdLen = 0;
	}

	g_Uart2Command.Buffer[g_Uart2Command.Index] = c;
	g_Uart2Command.Index++;
	g_Uart2Command.Index &= 0x3FF;//max is 1024

	if(g_Uart2Command.Index > UART_RX_DATA_LENGTH)
	{		
		if((g_Uart2Command.Index - UART_RX_DATA_LENGTH) > g_Uart2Command.Buffer[UART_RX_DATA_LENGTH])
		{
			g_bUart2Detected = 1; // command  buffer recieve ok
			g_Uart2CheckTick = 0;
			
			g_Uart2Command.Index = 0; // reset index of command buffer
			g_Uart2Command.u8Len = g_Uart2Command.Buffer[UART_RX_DATA_LENGTH];			
		}
	}
}

IV. Verification data header

uint8_t Uart2_Verify(void)
{
	if((g_Uart2Command.Buffer[UART_RX_HEADER] == UART_VALUE_HEADER)
		&&(g_Uart2Command.Buffer[UART_RX_ID] == UART_VALUE_ID)
		&&(g_Uart2Command.Buffer[UART_RX_CATEGORY] == UART_VALUE_CATEGORY)
		&&(g_Uart2Command.Buffer[UART_RX_PAGE] == UART_VALUE_PAGE)
		&&(g_Uart2Command.Buffer[UART_RX_FUNC] == UART_VALUE_FUNC)
		&&(g_Uart2Command.Buffer[UART_RX_CONTROL] == UART_VALUE_CONTROL)
	){

		return 1;
	}
	
	return 0;
}

Parity bit can define your own