com.c

讲解了串口通讯的几个实例

#ifndef COM_C
#define COM_C

#include "com.h"
#include "union.h"
#if !defined(_WIN32)

void BaudRate(int comPort, int baud)
{
    unsigned int comBase = comPort==COM1 ? COM1_BASE_ADRR : COM2_BASE_ADRR;
    outportb(comBase+COM_LCR, DLAB);    // DLAB=1
    outpw(comBase+COM_LSB, baud);
}

void DataFormat(int comPort, unsigned char format)
{
    unsigned int comBase = comPort==COM1 ? COM1_BASE_ADRR : COM2_BASE_ADRR;
    outportb(comBase+COM_LCR, (~DLAB)&format);  // DLAB=0
}

void InterruptType(int comPort, unsigned char intType)
{
    unsigned int comBase = comPort==COM1 ? COM1_BASE_ADRR : COM2_BASE_ADRR;
    outportb(comBase+COM_MCR, 0x0b);            // OUT2=RTS=DTR=0, needed
    outportb(comBase+COM_IER, intType);
}

void interrupt ( *MountISR(int comPort, void interrupt (*pNew)(void)) )
{
    void interrupt (*pOld)(void);
	int intNo = comPort==0 ? COM1_INT_NO : COM2_INT_NO;
	pOld =  getvect(intNo);
	setvect(intNo, pNew);
	return pOld;
}

void COM1RX(unsigned char c)
{
	static int idx = 0;
	Sendunion.Sendstring[idx++] = c;
	com1Rx_len++;
	if(idx==58)
	{
		if(CRC16(Sendunion.Sendstring,56)==Sendunion.s1.CheckValue)
		{
			ReceiveDone=1;
			com1Count ++;

            idx=0 ;
        }
    }

}


void COM2RX(unsigned char c)
{
    c=c;
    
}
static int com1TXLen, com1TXIdx, com2TXLen, com2TXIdx;
static unsigned char *pcom1TXBuf, *pcom2TXBuf;
int com1TX=0, com2TX=0, com1RX=0, com2RX=0, com1TXBusy=0, com2TXBusy=0;

void interrupt COM1ISR(void)
{
    unsigned char intType;

    intType = inport(COM1_BASE_ADRR+COM_IIR);

next_com1:
    if(intType&INT_SCR_TX)  //transmit interrupt ISR
    {
        if(com1TXIdx<com1TXLen)
        {
            com1TX ++;
            WriteCOM1(pcom1TXBuf[com1TXIdx++]);
        }
        else
            com1TXBusy = 0;
    }
    if(intType&INT_SCR_RX) //receive interrupt ISR
    {
        com1RX ++;
        COM1RX(ReadCOM1());
    }

    intType = inport(COM1_BASE_ADRR+COM_IIR);
    if(!(intType&INT_SCR_NO))
    goto next_com1;

    outportb(0x20,0x20);
}

void interrupt COM2ISR(void)
{
    unsigned char intType, c;

    intType = inport(COM2_BASE_ADRR+COM_IIR);

next_com2:
    if(intType&INT_SCR_TX) //transmit interrupt ISR
    {
        if(com2TXIdx<com2TXLen)
        {
            com2TX ++;
            WriteCOM2(pcom2TXBuf[com2TXIdx++]);
        }
        else
        com2TXBusy = 0;
    }
    if(intType&INT_SCR_RX) //receive interrupt ISR
    {
        com2RX ++;
        COM2RX(ReadCOM2());
    }
    
    intType = inport(COM2_BASE_ADRR+COM_IIR);
    if(!(intType&INT_SCR_NO))
        goto next_com2;
    
    outportb(0x20,0x20);
}

void OpenCOM(int comPort, int baud, unsigned char format, unsigned char intType)
{
    unsigned char oldIntMask  = inportb(0x21);
    disable();
    BaudRate(comPort, baud);
    DataFormat(comPort, format);
    InterruptType(comPort, intType);
    if(comPort==COM1)
    {
        MountISR(COM1, COM1ISR);
        outportb(0x21, oldIntMask&~COM1_INT_MASK);
    }
    else
    {
        MountISR(COM2, COM2ISR);
        outportb(0x21, oldIntMask&~COM2_INT_MASK);
    }
    enable();
}

void CloseCOM(int comPort)
{
    unsigned int comBase = comPort==COM1 ? COM1_BASE_ADRR : COM2_BASE_ADRR;
    unsigned char oldIntMask = inportb(0x21);
    disable();
    outportb(0x21, oldIntMask|(comPort==COM1 ? COM1_INT_MASK : COM2_INT_MASK));
    outportb(comBase+COM_MCR, 0x00);
    outportb(comBase+COM_IER, 0X00);
    enable();
}

void StartSend(int comPort, unsigned char comTXBuf[], int lenBuf)
{
    if(comPort==COM1)
    {
        com1TXIdx = 0;
        com1TXLen = lenBuf;
        pcom1TXBuf = comTXBuf;
        if( com1TXIdx<com1TXLen )
        {
            com1TX ++;
            WriteCOM1(pcom1TXBuf[com1TXIdx++]);
            com1TXBusy = 1;
        }
    }
    else
    {
        com2TXIdx = 0;
        com2TXLen = lenBuf;
        pcom2TXBuf = comTXBuf;
        if( com2TXIdx<com2TXLen )
        {
            com2TX ++;
            WriteCOM2(pcom2TXBuf[com2TXIdx++]);
            com2TXBusy = 1;
        }
    }
}

#endif /* _WIN32 */

char* i2s(short int i, char s[])
{
    char *p = (char*)&i;
#if EX_INV==1
    s[0] = p[1]; s[1] = p[0];
#else
    s[0] = p[0]; s[1] = p[1];
#endif
    return s;
}

char* l2s(long l, char s[])
{
    char *p = (char*)&l;
#if EX_INV==1
    s[0] = p[3]; s[1] = p[2]; s[2] = p[1]; s[3] = p[0];
#else
    s[0] = p[0]; s[1] = p[1]; s[2] = p[2]; s[3] = p[3];
#endif
    return s;
}

char* f2s(float f, char s[])
{
    char *p = (char*)&f;
#if EX_INV==1
    s[0] = p[3]; s[1] = p[2]; s[2] = p[1]; s[3] = p[0];
#else
    s[0] = p[0]; s[1] = p[1]; s[2] = p[2]; s[3] = p[3];
#endif
    return s;
}

char* d2s(double d, char s[])
{
    char *p = (char*)&d;
#if EX_INV==1
    s[0] = p[7]; s[1] = p[6]; s[2] = p[5]; s[3] = p[4];
    s[4] = p[3]; s[5] = p[2]; s[6] = p[1]; s[7] = p[0];
#else
    s[0] = p[0]; s[1] = p[1]; s[2] = p[2]; s[3] = p[3];
    s[4] = p[4]; s[5] = p[5]; s[6] = p[6]; s[7] = p[7];
#endif
    return s;
}

short int s2i(char s[])
{
    union{ 
        short int i;
        char c[2];
    } u;
#if EX_INV==1
    u.c[0] = s[1]; u.c[1] = s[0];
#else
    u.c[0] = s[0]; u.c[1] = s[1];
#endif
    return u.i;
}

long s2l(char s[])
{
    union{ 
        long l;
        char c[4];
    } u;
#if EX_INV==1
    u.c[0] = s[3]; u.c[1] = s[2]; u.c[2] = s[1]; u.c[3] = s[0];
#else
    u.c[0] = s[0]; u.c[1] = s[1]; u.c[2] = s[2]; u.c[3] = s[3];
#endif
    return u.l;
}

float s2f(char s[])
{
    union{ 
        float f;
        char c[4];
    } u;
#if EX_INV==1
    u.c[0] = s[3]; u.c[1] = s[2]; u.c[2] = s[1]; u.c[3] = s[0];
#else
    u.c[0] = s[0]; u.c[1] = s[1]; u.c[2] = s[2]; u.c[3] = s[3];
#endif
    return u.f;
}

double s2d(char s[])
{
    union{ 
        double d;
        char c[8];
    } u;
#if EX_INV==1
    u.c[0] = s[7]; u.c[1] = s[6]; u.c[2] = s[5]; u.c[3] = s[4];
    u.c[4] = s[3]; u.c[5] = s[2]; u.c[6] = s[1]; u.c[7] = s[0];
#else
    u.c[0] = s[0]; u.c[1] = s[1]; u.c[2] = s[2]; u.c[3] = s[3];
    u.c[4] = s[4]; u.c[5] = s[5]; u.c[6] = s[6]; u.c[7] = s[7];
#endif
    return u.d;
}

unsigned char CheckSum(unsigned char data[], int length)
{
    int i;
    unsigned char sum=0;
    for(i=0; i<length; i++)
        sum += data[i];
    return sum;
}
unsigned int CheckSum1(unsigned char data[], int length, unsigned char sum)
{
    return (CheckSum(data, length)==sum);
}

static unsigned short crc16_reverse_byte(unsigned char byte, unsigned short accum)
{
    unsigned short genpoly = 0xA001; 
    unsigned short data = 0x0000;
    int i;
    data = data|byte;
    for(i=0; i<8; i++)
    {
        if((data^accum)&0x0001)
            accum=(accum>>1)^genpoly;
        else
            accum>>=1;
        data>>=1;
    }
    return accum;
}

unsigned short CRC16(unsigned char *frame, int frameLen)
{
    unsigned short accum=0x0000;
    int i;
    for(i=0; i<frameLen; i++)
        accum = crc16_reverse_byte(*(frame+i), accum);
    return accum;
}

char* str2frm(char *str, char *frm, int len)
{
    char c;
    int i;
    unsigned short crc;
    
    frm[0]=0x01;
    for(i=0; i<len; i++)
    {
        c = str[i];
        frm[i*2+1] = (c&0x0f)|0x30;
        frm[i*2+2] = (c>>4)|0x30;
    }
    crc = CRC16(str, len);
    c = (char)(crc%256);
    frm[i*2+1] = (c&0x0f)|0x30;
    frm[i*2+2] = (c>>4)|0x30;
    c = (char)(crc>>8);
    frm[i*2+3] = (c&0x0f)|0x30;
    frm[i*2+4] = (c>>4)|0x30;
    frm[i*2+5] = 0x04;
    frm[i*2+6] = 0x00;
    return frm;
}

char* frm2str(char *frm, char *str, int len)
{
    int i;
    
    for(i=0; i<len/2-1; i++)
        str[i] = (frm[i*2+1]&0x0f) | ((frm[i*2+2]<<4)&0xf0);
    str[i] = 0x00;
    return str;
}

#endif /* COM_C */