关于IO口的自定义通信协议设计

设计一个通信协议需要start、end、数据0，数据1，这样就组成了一个最基本的通信协议。

要考虑到有运行误差的情况，加了误差之后以上四个信号也不会相互干扰，就是说加上误差后，0也不会变成1，1也不会变成0。

发送和接收的数据最好自己加校验，这样可以避免数据错误。

/*********************************************
 * 设计一个协议
 * start： 3ms高 1ms低
 * end  ： 1.5ms高 1.5ms低 //end的低电平持续时间是没有进行判断的，感觉没必要，想要的可以自己加上
 * 0    ： 700us高 300us低
 * 1    ： 300us高 700us低
 * 空闲态:低电平
 * *******************************************/
typedef unsigned char uint8_t;
typedef unsigned short uint16_t;

#define _RECV_IO //接收的IO口 
#define _SEND_IO //发送的IO口

#define USE_RECV //使用接收功能就打开注释,不使用就注释掉,默认使用
#define USE_SEND //使用发送功能就打开注释,不使用就注释掉,默认使用
         
#define n_100US_100US    (1)//中断时间是100us
#define BASE_TIME_TICK   (1*(n_100US_100US))
#define START_HIGH_TIME	 (30*(BASE_TIME_TICK))
#define START_LOW_TIME 	 (10*(BASE_TIME_TICK))
#define END_HIGH_TIME  	 (15*(BASE_TIME_TICK))
#define END_LOW_TIME	 (15*(BASE_TIME_TICK)) 
#define START_END_PERMISSIBLE_ERROR (4*(BASE_TIME_TICK))//允许误差

#define ZERO_HIGH_TIME	 (7*(BASE_TIME_TICK))
#define ZERO_LOW_TIME	 (3*(BASE_TIME_TICK))
#define ONE_HIGH_TIME	 (3*(BASE_TIME_TICK))
#define ONE_LOW_TIME	 (7*(BASE_TIME_TICK))
#define ZERO_ONE_PERMISSIBLE_ERROR (1*(BASE_TIME_TICK))//允许误差

#define MAX_ERROR_TIME 250//最大的时间限制


#define PROTOCOL_DATA_LENGTH 8//发送和接收数据的长度

typedef enum{
	n_StartHigh=0,
	n_StartLow,
	n_DataTransmission,
	n_EndHigh,
	n_EndLow,
}StepEnum_t;

typedef struct
{
#ifdef USE_RECV
	//接收
	uint8_t RecvTempArr[PROTOCOL_DATA_LENGTH];
	StepEnum_t RecvStep;
	uint8_t RecvHighCount;//高电平计数值
	uint8_t RecvLowCount;//低电平计数值
	uint16_t RecvDataBitCount;//接收到数据的bit值
	uint8_t RecvOneBitFlag;//接收到了一个bit
	uint8_t RecvOkFlag;//接收完毕,根据这个标志位提取数据
	uint8_t RecvArr[PROTOCOL_DATA_LENGTH];//接收到的数据
#endif
#ifdef USE_SEND
	//发送
	uint8_t NeedSendFlag;//需要发送
	StepEnum_t SendStep;
	uint8_t SendCount;//计数值
	uint16_t SendDataBitCount;//发送数据的bit值
	uint8_t OnSendingOneBitFlag;//正在发送了一个bit
	uint8_t SendingBit;//要发送的bit：0或1
	uint8_t SendArr[PROTOCOL_DATA_LENGTH];//要发送的数据
#endif
}ProtocolDesignStruct_t;

ProtocolDesignStruct_t Protocol;

void TimerInterrupt(void)//100us
{
	uint8_t i;
	uint8_t sendHighTime;
	uint8_t sendTotalTime;
#ifdef USE_RECV
	switch(Protocol.RecvStep)
	{
		case n_StartHigh:
			if(_RECV_IO)
			{
				if(Protocol.RecvHighCount < MAX_ERROR_TIME)Protocol.RecvHighCount++;
			}
			else
			{
				if(Protocol.RecvHighCount >= (START_HIGH_TIME-START_END_PERMISSIBLE_ERROR) && Protocol.RecvHighCount <= (START_HIGH_TIME+START_END_PERMISSIBLE_ERROR))
				{
					Protocol.RecvStep = n_StartLow;
					Protocol.RecvHighCount = 0;
					Protocol.RecvLowCount = 1;
				}
				else//长度错误
				{
					Protocol.RecvHighCount = 0;
				}
			}
			break;
		case n_StartLow:
			if(_RECV_IO)
			{
				if(Protocol.RecvHighCount >= (START_LOW_TIME-START_END_PERMISSIBLE_ERROR) && Protocol.RecvHighCount <= (START_LOW_TIME+START_END_PERMISSIBLE_ERROR))
				{
					Protocol.RecvStep = n_DataTransmission;
					for(i=0;i<PROTOCOL_DATA_LENGTH;i++)//要接收数据了，先清0
					{
						Protocol.RecvTempArr[i] = 0;
					}
					Protocol.RecvDataBitCount = 0；
					Protocol.RecvOneBitFlag = 0；
				}
				else
				{
					Protocol.RecvStep = n_StartHigh;//数据错误
				}
				Protocol.RecvHighCount = 1;
				Protocol.RecvLowCount = 0;
			}
			else
			{
				if(Protocol.RecvLowCount < MAX_ERROR_TIME)Protocol.RecvLowCount++;
			}
			break;
		case n_DataTransmission:
			if(_RECV_IO)
			{
				if(Protocol.RecvOneBitFlag == 0)//还没接收到1个字节
				{
					if(Protocol.RecvHighCount < MAX_ERROR_TIME)Protocol.RecvHighCount++;
				}
				else
				{
					if((Protocol.RecvHighCount >= ZERO_HIGH_TIME-ZERO_ONE_PERMISSIBLE_ERROR)&&(Protocol.RecvHighCount <= ZERO_HIGH_TIME+ZERO_ONE_PERMISSIBLE_ERROR)
						&&(Protocol.RecvLowCount >= ZERO_LOW_TIME-ZERO_ONE_PERMISSIBLE_ERROR)&&(Protocol.RecvLowCount <= ZERO_LOW_TIME+ZERO_ONE_PERMISSIBLE_ERROR) )//接收到0
					{
						Protocol.RecvDataBitCount++;
					}
					else if((Protocol.RecvHighCount >= ONE_HIGH_TIME-ZERO_ONE_PERMISSIBLE_ERROR)&&(Protocol.RecvHighCount <= ONE_HIGH_TIME+ZERO_ONE_PERMISSIBLE_ERROR)
						&&(Protocol.RecvLowCount >= ONE_LOW_TIME-ZERO_ONE_PERMISSIBLE_ERROR)&&(Protocol.RecvLowCount <= ONE_LOW_TIME+ZERO_ONE_PERMISSIBLE_ERROR) )//接收到1
					{
						Protocol.RecvTempArr[Protocol.RecvDataBitCount>>3] |= (0X01)<<(Protocol.RecvDataBitCount&0X0007);
						Protocol.RecvDataBitCount++;
					}
					else
					{
						Protocol.RecvStep = n_StartHigh;//数据错误
					}
					if(Protocol.RecvDataBitCount >= (PROTOCOL_DATA_LENGTH<<3))//数据接收完毕
					{
						Protocol.RecvStep = n_End;
					}
					Protocol.RecvHighCount = 1;
					Protocol.RecvOneBitFlag = 0;//重新接收一个字节
				}
			}
			else
			{
				if(Protocol.RecvLowCount < MAX_ERROR_TIME)Protocol.RecvLowCount++;
				Protocol.RecvOneBitFlag = 1;//已经接收到1个字节了
			}
			break;
		case n_EndHigh:
			if(_RECV_IO)
			{
				if(Protocol.RecvHighCount < MAX_ERROR_TIME)Protocol.RecvHighCount++;
			}
			else
			{
				if(Protocol.RecvHighCount >= (END_HIGH_TIME-START_END_PERMISSIBLE_ERROR) && Protocol.RecvHighCount <= (END_HIGH_TIME+START_END_PERMISSIBLE_ERROR))
				{
					for(i=0;i<PROTOCOL_DATA_LENGTH;i++)
					{
						Protocol.RecvArr[i] = Protocol.RecvTempArr[i];
					}
					Protocol.RecvOkFlag = 1;//接收到数据了
				}
				Protocol.RecvStep = n_StartHigh;
				Protocol.RecvHighCount = 0;
				Protocol.RecvLowCount = 0;
			}
			break;
		default:
			Protocol.RecvStep = n_StartHigh;
			Protocol.RecvHighCount = 0;
			Protocol.RecvLowCount = 0;
			break;
	}
#endif

#ifdef USE_SEND
	if(Protocol.NeedSendFlag)
	{
		switch(Protocol.SendStep)
		{
			case n_StartHigh:
				_SEND_IO = 1;
				if(++Protocol.SendCount >= START_HIGH_TIME)
				{
					Protocol.SendCount = 0;
					Protocol.SendStep = n_StartLow;
				}
				break;
			case n_StartLow:
				_SEND_IO = 0;
				if(++Protocol.SendCount >= START_LOW_TIME)
				{
					Protocol.SendCount = 0;
					Protocol.SendStep = n_DataTransmission;
					Protocol.SendDataBitCount = 0;//还未发送
					Protocol.OnSendingOneBitFlag = 0;//还未发送
				}
				break;
			case n_DataTransmission:
				if(Protocol.OnSendingOneBitFlag == 0)
				{
					//获取bit值
					if(Protocol.SendArr[Protocol.SendDataBitCount>>3]&(0X0001<<(Protocol.SendDataBitCount&0X0007)))Protocol.SendingBit = 1;
					else Protocol.SendingBit = 0;	
					Protocol.SendDataBitCount++;
					Protocol.OnSendingOneBitFlag = 1;
				}
				//获取高低电平时间
				if(Protocol.SendingBit)
				{
					sendHighTime = ONE_HIGH_TIME;
					sendTotalTime = ONE_HIGH_TIME + ONE_LOW_TIME;
				}
				else
				{
					sendHighTime = ZERO_HIGH_TIME;
					sendTotalTime = ZERO_HIGH_TIME + ZERO_LOW_TIME;
				}
				if(Protocol.SendCount < sendHighTime)
				{
					_SEND_IO = 1;
				}
				else
				{
					_SEND_IO = 0;
				}
				if(++Protocol.SendCount >= sendTotalTime)
				{
					Protocol.SendCount = 0;
					Protocol.OnSendingOneBitFlag = 0;
					if(Protocol.SendDataBitCount >= (PROTOCOL_DATA_LENGTH<<3))//数据发送完毕
					{
						Protocol.SendStep = n_EndHigh;
					}
				}
				break;
			case n_EndHigh:
				_SEND_IO = 1;
				if(++Protocol.SendCount >= END_HIGH_TIME)
				{
					Protocol.SendCount = 0;
					Protocol.SendStep = n_EndLow;
				}
				break;
			case n_EndLow:
				_SEND_IO = 0;
				if(++Protocol.SendCount >= END_LOW_TIME)
				{
					Protocol.SendCount = 0;
					Protocol.SendStep = n_StartHigh;
					Protocol.NeedSendFlag = 0;//发送完成
				}
				break;
			default:
				Protocol.NeedSendFlag = 0;
				break;
		}
	}
	else
	{
		_SEND_IO = 0;
		Protocol.SendStep = n_StartHigh;
		Protocol.SendCount = 0;
	}
#endif
}