Specific Area Message Encoding (S.A.M.E.)

[Archangel]

Google.
http://www.weather.gov/nwr/nwrsame.htm
http://www.bookrags.com/wiki/Specifi...ssage_Encoding

[Ryan7777]

I kind of already know that much info, its just the baud rate stuff and other things that are making my head hurt. 520.83 BAUD and no Stop bit seems to rule out using serin or hserin, correct me if im wrong and make fun of me if you wish. I was simply going to handle the 2083.3 HZ Mark tone 1562.5Hz Space tones with a couple of 567 tone decoders and a comparator. That would at least get me some TTL 1's and 0's to work with. But im lost on how to handle the data as far as timing goes. If it were 9600 8n1 i'd have no trouble decoding it.
Any idea's?

[mackrackit]

I think in this case
baud would equal bps.

[Archangel]

. . . and make fun of me if you wish . . . .

Oh hell no, 1st off not my style, second off, you're probably better at this than I am.

[Ryan7777]

But some people round here can't seem to help themselves when it comes to a little slap over the head. I don't mind, sometimes I need it. I think I'll let this post lay for a while and see if anyone has any advice. But I'm thinking SHIFTIN might work, then i'll have to figure out a way to clock in and count the number of incoming bits or bytes. The preamble alone is 16 bytes of $AB repeating. Then the message itself, which is what i want to decode, can be up to 268 bytes long. but it is supposed to always start with ASCII ZCZC to let you know the message is starting, then wait for "NNNN" which is the end of the message. Everything is delimited with a "dash", so it shouldn't be so hard to break the message down. I've never worked with SHIFTIN before, and know nothing of interupts, so if anyone has any advice or a better way, let me know!

[mackrackit]

It most times gets me in trouble... but I have been thinking.

8N0 sounds like synchronous, so would a PIC with USART work?
Mister E's multicalc give this for 520.83 baud.

DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
DEFINE HSER_TXSTA 20h ' Enable transmit, BRGH = 0
DEFINE HSER_SPBRG 255 ' 520.83 Baud @ 20MHz, 134.43%
DEFINE HSER_CLROERR 1 ' Clear overflow automatically

And...being 1 STOP bit is a signal going from low to high, and the last bit of SAME is always 0
would that look like a STOP bit?

If I did my math correctly...
SERIN2 MODES
520.83 baud in TRUE mode is
1900
520.83 baud in INVERTED mode is
5996

Maybe someone with a BRAIN will correct me