Serial addressing

[DynamoBen]

The problem is making the UART aware of the fact that a byte in the data packet is an address. With most protocols the address is not the first byte. It would be very complex to implement that.

The "hard way" is not too bad. I'm doing a project now that responds to the node address and 00 as a multicase discovery address. Its not too bad.

[electronicsuk]

I agree it would be more complicated to do address detect without the 9th bit, but it would be relatively easy to keep the 9th bit system but also to have the PIC compare the received address to one with a register, and ignore any addresses not designated for that particular micro.

Alternatively design a protocol where the address bytes can never occur as a data byte, for example all decimal values above 100 can be used for addressing only. The trouble I had before with this system is that every time the UART received a byte of data, it would have to be read and checked to see if it was an address, even if it was only a data byte. There was absolutely no way of knowing without reading the data.

On its own this wouldn't be a problem, but at the same time I'm keeping an eye on a zero crossing detector and driving 8 triac dimming outputs. When sending out large amounts of data the lamps being driven by the triacs would flicker slightly as the micro was having to take some time out from the dimming routine, go read the UART and make a comparison.