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
>
>

It's not as simple as that. You have to generate the DMX other timing
as well. eg. Break, MAB, etc. The DMX stream is not just a series of
bytes @ 250KB. The timing is what syncs the receivers to the stream.
David...

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