[En-Nut-Discussion] Ethernut & DMX

[Michael G. Svob]

Greetings,

Does anyone have experience using an Ethernut to receive and process DMX
lighting signals? I'm using a Maxim MAX3084E RS-485 tranceiver chip feeding
into USART 0, with baud rate set to 250K, 8 data bits, no parity, and 2 stop
bits. Problem is, I can synch on and receive the data (from a known good DMX
source), but the received data is a bit funky. For one thing, the MS bit of
the data is always "1", so for example data that should be 1 (0x01) is
actually returned as 129 (0x81). Also (ignoring the MS bit), for much (but
not all) of the range 0-255, other seemingly random bits seem to get set
incorrectly for no apparent reason. For example, the value 20 (binary 0001
0100) is received as both 142 (1000 1110) and 156 (1001 1100).

For the record, I've tried different baud rates, number of data bits, number
of stop bits, etc., but with no success. For what it's worth, I also get
exactly the same results with an STK500 and an ATMega16.

Thanks in advance for any help that can be extended.

Best Regards,
Michael Svob