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I am driving the USART in a 16F877 from a little $5 garage door opener type of UHF receiver. When there is no transmitted signal the receiver puts out noise and the USART generates junk characters -- which I can accomodate with packet structure and initial transmission of a bunch of characters for the USART to sync up on.

 

Somewhere -- I think it was in this forum -- somebody did some deep thinking and came up with an optimum string of characters to send that will allow the USART to sync quickly, but I can't seem to find it.

 

Anybody got any thoughts on the optimal start up sync string....

 

Regards

Rye

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After a little Google research and the correct search terms I managed to come up with two really helpful articles about making the transition from 'empty' channel noise (aka random 'data') to a serial data transmission using the little inexpensive "dumb" receivers.

 

Micro Linear

 

and

 

RadioTronix

 

Of course, it you are using the slightly more expensive receivers with RSSI you could probably get away with just that, but both methods might be better than just one.

 

A belt and suspenders (and a good packet protocol) never hurt anybody.

 

Rye

:(

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Hi ryeg,

 

Based on my own experience if your package header and tail has bit 7 = 1 and data in the middle have bit 7 = 0, including the checksum byte, you can do the job without troubles.

 

Of course data bytes must have some work before send and also some work after received.

 

Regards,

joli

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