serial port does not work on PC104

Hi Everyone, I am now using a PC104 (model: nano-4386A, vendor IEI world), which will be running linux.

Now I installed fedora core 6(kernel 2.6). but COM1 does not work at all. I have installed winXP on the same hardware platform, COM1 works well. So the hardware is OK. Here is detailed info.

(1) hardware configuration: NANO-4386A, Pentium 1.6GHz, Sandisk 8GB CF card, 1GB Ram, no hard disk. Keep the jumpers on the board as default state. (2) Loop back connect the COM1, that is connecting TXT to RXD. It is a

9 pin port. send and receive through the same port. (3) Install linux OS(fedora core 2.6, kernel 2.6) on it. (4) Test using sct, a software tool for serial port debugging. (5) NO output through COM1, cannot receive either. (6) The same program sct works well on my desktop, which installed the same OS using the same DVD disk. By the way, there is 6 serial ports on the board.Even if I disable the other 5 in BIOS, the only /dev/ttyS0 does not work. (7) I can see the io address and IRQ number is correct by "dmesg | more tty*" Is there anything I should pay attention to? Thank you!
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Check out /etc/inittab. Maybe a getty keeps ttyS0 open allowing you to log in on it, preventing other programs from using the port.

Karl Olsen

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Karl Olsen

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You could check if /proc/interrupts report anything for your serial ports IRQ.

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ls -l the device and see who owns it. And what the read/write permission is. That will show if, as another poster said, there is a process sitting there waiting for a login. The owner will shift from "root" when somebody else opens up the device and the write permissions often drop to 600 or 620 from a default of 660 or 666.

Then you can (as root) "stty -all

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Mark Zenier

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