Problem with extra serial ports...

Problem with extra serial ports...

Post by Jjjenn » Mon, 26 Jul 1999 04:00:00

I am trying to add 2 more serial ports to my SuSE 6.1 installation.
ttyS0 and ttyS1 (irq 4 & 3) work fine, but ttyS2 and ttyS3 (on irq 11
and 12) only pass characters at a VERy slow rate. I tried SETSERIAL but
it doesn't seem to help.

What' the trick? Do I need to recompile the kernal?

Also, what advice do you have for mutliple port serial cards?  I'd like
to have a few modems, as well as packet radio TNCs on the machine.



1. Problems with extra serial ports

Hi there

I'm trying to get our serial multiport board, with a ST16C554 chip,
to work. I assume I should use setserial to get those extra ports
to work on my command, but I must have set something up completely

Whenever I write to it, it takes 5-6 seconds before something comes
up on the other terminal, and it's always 16 bytes (as large as the
FIFO buffers on the chip). There are ports to check for work pending,
but it still behaves in the same way.

Here's how I use setserial:

/sbin/setserial /dev/ttyS4 uart 16550A port 0x240 irq 9 low_latency
baud_base 115200 divisor 3 ^fourport set_multiport port1 0x245
mask1 0x41 match1 0x40

Now the mask bits (0x41 = 01000001b) are:
Bit0: 0 = No data in receive holding register or FIFO
Bit6: 1 = Transmit holding register and transmit shift register are

Is there any obvious mistakes I make? What happens if I've chosen
an incorrect UART?

 Thanks /Marco

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