You are not clear as to whether the PC is a slave or a master.
If the former, just get a PCI DMX card and be done with with.
http://www.pro-music-news.com/html/studio/e20323so.htm

Or a cheap serial card and change the crystal so that
115.2kbps becomes 250khz. 1.8432Mhz -> 4Mhz.
If you are lucky the embedded PC has a dedicated clock crystal
for the multifunction I/O chip, and you could change that.
A lot of MF chips start with 12 or 24mhz and can be programmed
to run with a higher starting baud rate divisor. (e.g. no
divide by 13 before the rate select mux.)

What's your time worth to build and debug a PIC baud rate changer?

Robert

Herbert Graf wrote:
>
> > I'm working on a project that requires converting unidirectional
> > data from one baudrate to another. If anyone has ideas on an elegant
> > and inexpensive way to do this, it would be appreciated.
> >
> > The converter is for a DMX transmitter. DMX is the standard protocol
> > used in the entertainment industry for controlling lighting equipment
> > such as dimmers, colour changers, fog machines, etc. It is electrically
> > RS-485, and the data is 250kbps.
> >
> > The crux is that I am interfacing it with an embedded PC using the
> > RS-232 port which runs at 115.2kbps. Of course there is a bottleneck,
> > but it's ok because the data being sent is generated less often then
> > what would be needed to max out the DMX output.
> >
> > Here are my current thoughts on a solution:
> >
> > - 2 PICs connected together with either parallel or I2C
> > - a PIC with 2 UARTs (but the only ones are 64TQFP, not nice to solder)
> > - a PIC controlling a 16550 UART
> >
> > Any ideas would be greatly appreciated.
>
>         Check out the Maxim MAX3100, it's an SPI UART. I'm considering it for a
> project I have in mind that requires three UARTs. TTYL
>
> ----------------------------------
> Herbert's PIC Stuff:
> http://repatch.dyndns.org:8383/pic_stuff/
>
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