From: On Behalf Of Joe Barr
> I'm forwarding this post by the author of a great little program for
> digital amateur radio on Linux, because I'm curious whether or not the
> problem he is seeing can be resolved outside the kernel.
From: w1hkj [mailto:[email protected]]
> I am now convinced that the current serial port drivers
> available to us
> on the Linux platform WILL NOT support CW and/or RTTY that is
> software
> generated in a satisfactory manner.
I don't know what FSK/CW/RTTY/BAUDOT is.
> Direct access to the serial port(s) is a kernel perogative in Linux.
> Only kernel level drivers are allowed such port access.
Not true.
> Until such time as new information becomes available I am going to
> comment out all references to CW and / or FSK via RTS/DTR. I also
> question how useful the FSK on TxD (UART derived) might be to
> most users
> since the 45.45 baudrate is not available in the serial port driver.
> That function will also be commented out.
You may be confusing the old-style baud rate lookup table (B9600 et
al) with the actual capabilities of the serial port. The lookup table
has a limited number of baud rates. You can get more rates than that
using a custom divisor. Most motherboard-based serial ports are
clocked at 1.8432 Mhz. The UART does 16 samples per bit time, yielding
a max baud rate of 115200.
115200 / 25 yields 4608, which is a 1.4% error rate from 4545. This
may or may not be acceptable. 115200 / 2535 yields 45.44, which is a
0.01% error rate, which is likely acceptable.
> Sorry folks, but we win some and lose some.
We make serial port boards with very flexible UARTS. 4545 exactly is
achievable. 45.45 too. Linux supported.
..Stu
--
We make multiport serial products.
http://www.connecttech.com/
(800) 426-8979
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