Read/write serial port with Linux

May 05, 2004 2 Replies

Rate this thread:

Michael Hofmann 22 years ago

I want to read data off a serial device on /dev/ttyS1. What I need to do is send one ASCII character to the device, upon which it spits out 7 multi-character values, see below. The comm parameters are 1200Bd 8N1, no flow control. I have tried various approaches based on the serial programming HowTo and a few code fragments written for serial multimeters found on the net. However, I don't seem to be able to make any of this work. I can get the expected result by using a terminal emulator, but what I really want is a program or script that can do this. This has been bugging me for weeks now, but I don't seem to be able to make anything of the HowTo and progs. Any advice on how to approach this or a link to a more in-depth description?

Michael

Sent: F Rec'd: R:12,60;- 1,3;15;11,22;12,61;- 1,6;- 1,3;

Vote

Bryan Hackney 22 years ago

Try initializing like this:

This structure was obtained by using the 'stty raw' command, and then dumping the results.

struct termios tio_raw = { /*c_iflag*/ 0x0, /*c_oflag*/ 0x0, /*c_cflag*/ 0x18b2, /*c_lflag*/ 0x0, /*c_line*/ 0x0, { /*c_cc[0]*/ 0x0, /*c_cc[1]*/ 0x0, /*c_cc[2]*/ 0x0, /*c_cc[3]*/ 0x0, /*c_cc[4]*/ 0x0, /*c_cc[5]*/ 0x0, /*c_cc[6]*/ 0x1, /*c_cc[7]*/ 0x0, /*c_cc[8]*/ 0x0, /*c_cc[9]*/ 0x0, /*c_cc[10]*/ 0x0, /*c_cc[11]*/ 0x0, /*c_cc[12]*/ 0x62, /*c_cc[13]*/ 0x61, /*c_cc[14]*/ 0x69, /*c_cc[15]*/ 0xe, /*c_cc[16]*/ 0x7b, /*c_cc[17]*/ 0x8, /*c_cc[18]*/ 0x40, /*c_cc[19]*/ 0x0, /*c_cc[20]*/ 0x0, /*c_cc[21]*/ 0x0, /*c_cc[22]*/ 0x0, /*c_cc[23]*/ 0x0, /*c_cc[24]*/ 0x0, /*c_cc[25]*/ 0x0, /*c_cc[26]*/ 0x0, /*c_cc[27]*/ 0x0, /*c_cc[28]*/ 0x0, /*c_cc[29]*/ 0x0, /*c_cc[30]*/ 0x0, /*c_cc[31]*/ 0x0, }, };

void Serial::init( ) {

tio_raw.c_cflag = B115200 | CS8 | CLOCAL | CREAD; tcsetattr( fd, TCSANOW, &tio_raw);

}

Vote

Paul Taylor 22 years ago

I have found the serial howto difficult to work with. There is another serial programming guide, by a guy named Michael Sweet, and that guide IMHO is far superior. I did a search on google and found it at:

formatting link

HTH

Paul.

-- Remove _rem_ before reply> I want to read data off a serial device on /dev/ttyS1. What I need to do

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required