High speed RS232 card woes

High speed RS232 card woes

[Nickie Deuxyeux]

Hello everyone,

I am trying to setup a 2-port high-speed RS232 card (MP954R2) under 
Gentoo Linux 2006.0. The card has an Oxford Semi OX16PCI954 chip and a 
clock oscillator at 1.8432 Mhz.

I am running the latest 2.6.15-gentoo-r1 kernel with the following 
related .config options.

*Code:*

CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_8250_EXTENDED=y
CONFIG_SERIAL_8250_SHARE_IRQ=y



Here goes the lspci output...

*Code:*

00:0d.0 Serial controller: Oxford Semiconductor Ltd OX16PCI952 (Dual 
16950 UART) (prog-if 06 [16950])
        Subsystem: Oxford Semiconductor Ltd Unknown device 0001
        Flags: medium devsel, IRQ 16
        I/O ports at 2058 [size=8]
        I/O ports at 2050 [size=8]
        I/O ports at 2060 [size=32]
        Memory at f4104000 (32-bit, non-prefetchable) [size=4K]
        Memory at f4103000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [40] Power Management version 1



This is my setserial output...

*Code:*

 setserial -g -a /dev/ttyS*
/dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4
        Baud_base: 115200, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_normal skip_test

/dev/ttyS1, Line 1, UART: 16550A, Port: 0x02f8, IRQ: 3
        Baud_base: 115200, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_normal skip_test

/dev/ttyS2, Line 2, UART: 16950/954, Port: 0x2058, IRQ: 16
        Baud_base: 115200, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_shi skip_test

/dev/ttyS3, Line 3, UART: 16950/954, Port: 0x2050, IRQ: 16
        Baud_base: 115200, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_shi skip_test



This is my /etc/serial.conf

*Code:*

/dev/ttyS2 baud_base 115200 spd_shi
/dev/ttyS3 baud_base 115200 spd_shi


The serial script is activated at boot-time.

The main problem is, the device I am trying to connect (CDMA terminal) 
can only work with a baud rate of 230400. I can't seem to get the device 
to respond to AT commands in minicom, though I have absolutely no 
problems under Windows, the device works flawlessly using the same card.

I've tried setting minicom to 230k and to 38.4k, tried playing with 
"baud_base" and other settings like flow control to no avail.

There must be something I am doing wrong here, but I ran out of ideas! 
I've also been informed that I may need an alternative driver, but I 
have no idea where to find one.

Please help! Thanks in advance for any replies!

Re: High speed RS232 card woes

[Paul Fulghum]

On Wed, 2006-03-15 at 13:16 +0300, Nickie Deuxyeux wrote:
> I am trying to setup a 2-port high-speed RS232 card (MP954R2) under 
> Gentoo Linux 2006.0. The card has an Oxford Semi OX16PCI954 chip and a 
> clock oscillator at 1.8432 Mhz.
...
> The main problem is, the device I am trying to connect (CDMA terminal) 
> can only work with a baud rate of 230400. I can't seem to get the device 
> to respond to AT commands in minicom, though I have absolutely no 
> problems under Windows, the device works flawlessly using the same card.

The OX16PCI954 defaults to a standard oversampling of 16
which yields a max 115200bps for a 1.8432MHz clock.

This device has a non-standard Times Clock Register (TCR) that
can be used to lower the oversampling (minimum of 4)
and allow higher speeds (up to 460,800bps) with the 1.8432MHz clock.

But the driver has to know how to set that. I don't see
that the standard 8250.c serial driver has any knowledge of this
register.

The Windows drivers must know how to set this correctly.

-- 
Paul Fulghum
Microgate Systems, Ltd