How to make /dev/ttyS0 automatic control DTR for TX/RX

ZeRoN · 12-19-2004, 02:05 PM

Dear All,

How to make /dev/ttyS0 automatically control DTR for TX/RX.

I mean, When I write to /dev/ttyS0, DTR=ON,send a character,DTR=OFF, repeat until sent all characters in buffer.

THX IN ADV.
ZeRoN

cppkid · 12-27-2004, 12:51 AM

All i can do for you is that i can provide you the way to clear and set DTR. Here it is....

You have to #include<sys/ioctl.h>
m_hCom is the handle to the Port or ttyS0

Code:

//________________________Set_DTR__________________bool Set_DTR(void)
{
int nRet;
int status;
status = 0;
nRet = ioctl(m_hCom, TIOCMGET,&status);
	if(nRet < 0) return FALSE;
status |= TIOCM_DTR;
nRet = ioctl(m_hCom, TIOCMSET, &status);
	if(nRet < 0) return FALSE;
return TRUE;
}


//________________________Clr_DTR__________________bool Clr_DTR(void)
{
int nRet;
int status;
status = 0;
nRet = ioctl(m_hCom, TIOCMGET,&status);
	if(nRet < 0) return FALSE;
status &= ~TIOCM_DTR;
nRet = ioctl(m_hCom, TIOCMSET, &status);
	if(nRet < 0) return FALSE;
return TRUE;
}