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can't get second serial port to work (ttyS1)

Discussion in 'Modding Forum' started by hedpe, Jul 5, 2005.

  1. hedpe

    hedpe Network Guru Member

    Hey all,

    I actually have a WAP54G, and followed the WRT54G dual serial port setup.

    I was able to get the first serial port to work, the serial console. I understand the following pinout about the WAP54G:

    O O O O 3.3v, 3.3v, Ground, Ground
    O O O O O ttyS0 output, Unknown, Unknown, ttyS0 input, Unknown

    By following this pinout, my first serial port works. So, therefore I only have 3 unknown pins left... 2 of them have to be a ttyS1 input, and ttyS0 output. So, my first theory was to try every single combination of these pins and I would eventually get a second serial port working. I tried this out, and I couldn't get the second serial port working.

    So then I read that I should just connect ttyS1 input, to ttyS0 output, and pull up my console and do a "cat /dev/tts/1 > /dev/tts/1", and if both input and output are together, I should get an echo back. Well... I tried all combination of wires again with this command, and got no echo.

    So then I kept googling and saw that the WRT54G tries to have both ports share the same IRQ, and this is bad? I really know simple basics about hardware, and I know that two things need seperate IRQs. So my question is, how do I check the IRQ with my serial port console, and how do I change the IRQ so that I can get the second serial port working?

    Or, if anyone has any more suggestions which could help me correctly pinout the last 3 pins so I can find the real ttyS1 in and out :)

    On boot:
    Code:
    Serial driver version 5.05c (2001-07-08) with MANY_PORTS SHARE_IRQ SERIAL_PCI enabled
    ttyS00 at 0xb8000300 (irq = 3) is a 16550A
    ttyS01 at 0xb8000400 (irq = 0) is a 16550A
    From Shell (make sure to expand the code):
    Code:
    # cat /proc/tty/driver/serial
    serinfo:1.0 driver:5.05c revision:2001-07-08
    0: uart:16550A port:B8000300 irq:3 baud:115740 tx:2190 rx:199 RTS|DTR
    1: uart:16550A port:B8000400 irq:0 tx:0 rx:0 CTS|DSR|CD
    
    Thanks!
    George
     
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