首先我們下載FreeModbus源碼,然後放到自己的工程中,新建一個MODBUS_TCP和PORT_TCP文件夾,然後將相關文件複製到裏面,如下圖所示:
然後修改porttcp中的代碼:
首先定義一個數組用於接收數據:
static UCHAR aucTCPBuf[MB_TCP_BUF_SIZE]; //接收緩衝區
然後在xMBTCPPortInit中初始化socket連接,然後監聽端口。
BOOL
xMBTCPPortInit( USHORT usTCPPort )
{
BOOL bOkay = FALSE;
// 偵聽端口 Modbus-TCP 端口
socket_init(SOCK_TCP_PORT,Sn_MR_TCP_TCP,local_tcp_port++,Sn_MR_ND_TCP);
listen_tcp_socket(SOCK_TCP_PORT);
bOkay = TRUE;
return bOkay;
}
然後在xMBTCPPortSendResponse函數中發送數據
BOOL
xMBTCPPortSendResponse(const UCHAR * pucMBTCPFrame, USHORT usTCPLength )
{
send_tcp_socket_data(SOCK_TCP_PORT,(UCHAR*)pucMBTCPFrame,usTCPLength);
return TRUE;
}
然後在xMBPortTCPPool執行接收和其他操作
BOOL
xMBPortTCPPool( void )
{
unsigned short int us_rlen;
unsigned char i;
i=get_tcp_socket_state(SOCK_TCP_PORT);
if(i==SOCK_ESTABLISHED_TCP)
{
if(get_tcp_socket_irq(SOCK_TCP_PORT) & Sn_IR_CON_TCP) //查看中斷有沒有發生
{
clear_tcp_socket_irq(SOCK_TCP_PORT, Sn_IR_CON_TCP); /*清除接收中斷標誌位*/
}
us_rlen=get_tcp_rx_buffer_size(SOCK_TCP_PORT); //獲取接收到的數據字節 /*定義len爲已接收數據的長度*/
if(us_rlen==0) //沒有接收到數據
return FALSE; //返回
else
{
recv_tcp_socket_data(SOCK_TCP_PORT,aucTCPBuf,us_rlen); //接收數據 /*接收來自Server的數據*/
printf("receive\r\n");
usTCPBufLen=us_rlen;
}
( void )xMBPortEventPost( EV_FRAME_RECEIVED ); //發送已接收到新數據到Modbus-TCP狀態機
}
else if(i==SOCK_CLOSED_TCP) //如果socket關閉
{
socket_init(SOCK_TCP_PORT,Sn_MR_TCP_TCP,local_tcp_port++,Sn_MR_ND_TCP);//重新初始化
}
else if(i==SOCK_INIT_TCP) //如果socket初始化完畢,監聽端口
{
listen_tcp_socket(SOCK_TCP_PORT);
}
else if(i==SOCK_CLOSE_WAIT_TCP) //如果socket等待關閉,關閉socket連接
{
close_tcp_socket(SOCK_TCP_PORT);
}
return TRUE;
}
其次還要實現讀線圈、寫線圈、讀離散輸入、寫保持寄存器、讀保持寄存器、讀輸入寄存器等功能,如下:
#define REG_INPUT_START 0x0001 //輸入寄存器起始地址
#define REG_INPUT_NREGS 8 //輸入寄存器數量
#define REG_HOLDING_START 0x0001 //保持寄存器起始地址
#define REG_HOLDING_NREGS 8 //保持寄存器數量
#define REG_COILS_START 0x0001 //線圈起始地址
#define REG_COILS_SIZE 16 //線圈數量
#define REG_DISCRETE_START 0x0001 //開關寄存器其實地址
#define REG_DISCRETE_SIZE 16 //開關寄存器數量
//輸入寄存器內容
uint16_t usRegInputBuf[REG_INPUT_NREGS] = {0x1000,0x1001,0x1002,0x1003,0x1004,0x1005,0x1006,0x1007};
//保持寄存器內容
uint16_t usRegHoldingBuf[REG_HOLDING_NREGS] = {0x2000,0x2001,0x2002,0x2003,0x2004,0x2005,0x2006,0x2007};
//線圈狀態
uint8_t ucRegCoilsBuf[REG_COILS_SIZE] = {0x01,0x01,0x00,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00};
//離散寄存器內容
uint8_t ucRegDiscreteBuf[REG_DISCRETE_SIZE] = {0x01,0x01,0x00,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x01};
/****************************************************************************
* 名 稱:eMBRegInputCB
* 功 能:讀取輸入寄存器,對應功能碼是 04 eMBFuncReadInputRegister
* 入口參數:pucRegBuffer: 數據緩存區,用於響應主機
* usAddress: 寄存器地址
* usNRegs: 要讀取的寄存器個數
* 出口參數:
* 注 意:上位機發來的 幀格式是: SlaveAddr(1 Byte)+FuncCode(1 Byte)
* +StartAddrHiByte(1 Byte)+StartAddrLoByte(1 Byte)
* +LenAddrHiByte(1 Byte)+LenAddrLoByte(1 Byte)+
* +CRCAddrHiByte(1 Byte)+CRCAddrLoByte(1 Byte)
* 3 區
****************************************************************************/
eMBErrorCode
eMBRegInputCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs )
{
eMBErrorCode eStatus = MB_ENOERR;
int iRegIndex;
if( ( usAddress >= REG_INPUT_START )
&& ( usAddress + usNRegs <= REG_INPUT_START + REG_INPUT_NREGS ) )
{
iRegIndex = ( int )( usAddress - REG_INPUT_START );
while( usNRegs > 0 )
{
*pucRegBuffer++ = ( UCHAR )( usRegInputBuf[iRegIndex] >> 8 );
*pucRegBuffer++ = ( UCHAR )( usRegInputBuf[iRegIndex] & 0xFF );
iRegIndex++;
usNRegs--;
}
}
else
{
eStatus = MB_ENOREG;
}
return eStatus;
}
/****************************************************************************
* 名 稱:eMBRegHoldingCB
* 功 能:對應功能碼有:06 寫保持寄存器 eMBFuncWriteHoldingRegister
* 16 寫多個保持寄存器 eMBFuncWriteMultipleHoldingRegister
* 03 讀保持寄存器 eMBFuncReadHoldingRegister
* 23 讀寫多個保持寄存器 eMBFuncReadWriteMultipleHoldingRegister
* 入口參數:pucRegBuffer: 數據緩存區,用於響應主機
* usAddress: 寄存器地址
* usNRegs: 要讀寫的寄存器個數
* eMode: 功能碼
* 出口參數:
* 注 意:4 區
****************************************************************************/
eMBErrorCode
eMBRegHoldingCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs, eMBRegisterMode eMode )
{
eMBErrorCode eStatus = MB_ENOERR;
int iRegIndex;
if((usAddress >= REG_HOLDING_START)&&\
((usAddress+usNRegs) <= (REG_HOLDING_START + REG_HOLDING_NREGS)))
{
iRegIndex = (int)(usAddress - REG_HOLDING_START);
switch(eMode)
{
case MB_REG_READ://讀 MB_REG_READ = 0
while(usNRegs > 0)
{
*pucRegBuffer++ = (u8)(usRegHoldingBuf[iRegIndex] >> 8);
*pucRegBuffer++ = (u8)(usRegHoldingBuf[iRegIndex] & 0xFF);
iRegIndex++;
usNRegs--;
}
break;
case MB_REG_WRITE://寫 MB_REG_WRITE = 0
while(usNRegs > 0)
{
usRegHoldingBuf[iRegIndex] = *pucRegBuffer++ << 8;
usRegHoldingBuf[iRegIndex] |= *pucRegBuffer++;
iRegIndex++;
usNRegs--;
}
break;
}
}
else//錯誤
{
eStatus = MB_ENOREG;
}
return eStatus;
}
/****************************************************************************
* 名 稱:eMBRegCoilsCB
* 功 能:對應功能碼有:01 讀線圈 eMBFuncReadCoils
* 05 寫線圈 eMBFuncWriteCoil
* 15 寫多個線圈 eMBFuncWriteMultipleCoils
* 入口參數:pucRegBuffer: 數據緩存區,用於響應主機
* usAddress: 線圈地址
* usNCoils: 要讀寫的線圈個數
* eMode: 功能碼
* 出口參數:
* 注 意:如繼電器
* 0 區
****************************************************************************/
eMBErrorCode
eMBRegCoilsCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNCoils, eMBRegisterMode eMode )
{
eMBErrorCode eStatus = MB_ENOERR;
int iRegIndex;
u8 i;
USHORT readNumber=usNCoils;
USHORT coilValue=0x0000;
if((usAddress >= REG_COILS_START)&&\
((usAddress+usNCoils) <= (REG_COILS_START + REG_COILS_SIZE)))
{
iRegIndex = (int)(usAddress + usNCoils-REG_COILS_START);
switch(eMode)
{
case MB_REG_READ://讀 MB_REG_READ = 0
for(i=0;i<usNCoils;i++)
{
readNumber--;
iRegIndex--;
coilValue|=ucRegCoilsBuf[iRegIndex]<<readNumber;
}
if(usNCoils<=8)
{
* pucRegBuffer=coilValue;
}
else
{
* pucRegBuffer++ = (coilValue)&0x00ff;
* pucRegBuffer++ = (coilValue>>8)&0x00ff;
}
break;
case MB_REG_WRITE://寫 MB_REG_WRITE = 1
while(usNCoils > 0)
{
// usRegHoldingBuf[iRegIndex] = *pucRegBuffer++ << 8;
// usRegHoldingBuf[iRegIndex] |= *pucRegBuffer++;
iRegIndex++;
usNCoils--;
}
break;
}
}
else//錯誤
{
eStatus = MB_ENOREG;
}
return eStatus;
}
/****************************************************************************
* 名 稱:eMBRegDiscreteCB
* 功 能:讀取離散寄存器,對應功能碼有:02 讀離散寄存器 eMBFuncReadDiscreteInputs
* 入口參數:pucRegBuffer: 數據緩存區,用於響應主機
* usAddress: 寄存器地址
* usNDiscrete: 要讀取的寄存器個數
* 出口參數:
* 注 意:1 區
****************************************************************************/
eMBErrorCode
eMBRegDiscreteCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNDiscrete )
{
eMBErrorCode eStatus = MB_ENOERR;
int iRegIndex;
u8 i;
USHORT readNumber=usNDiscrete;
USHORT coilValue=0x0000;
iRegIndex = (int)(usAddress + usNDiscrete-REG_DISCRETE_START);
if((usAddress >= REG_DISCRETE_START)&&\
((usAddress+usNDiscrete) <= (REG_DISCRETE_START + REG_DISCRETE_SIZE)))
{
for(i=0;i<usNDiscrete;i++)
{
readNumber--;
iRegIndex--;
coilValue|=ucRegDiscreteBuf[iRegIndex]<<readNumber;
}
if(usNDiscrete<=8)
{
* pucRegBuffer=coilValue;
}
else
{
* pucRegBuffer++ = (coilValue)&0x00ff;
* pucRegBuffer++ = (coilValue>>8)&0x00ff;
}
}
else
{
eStatus = MB_ENOREG;
}
return eStatus;
}