Quote Originally Posted by lerameur
By preconditioning you mean making sure the internal circuitry lets say capacitor will be ready . As in ready I mean not empty or full as to give a 1 instead of a 0 or the other way. BUt is there a start bit ? How does it know where the data start and end. I guess there is not start bit like in network communication, the training session replaces that . As en example, lets say the pic chip receives the 8bit is needs, on the next eight bit, it misses out (for a reason or another) a bit, Will it be taking its eight bit on the next sequence or simply drop the whole byte ? this is what I meant by how does it know the end and start of a byte series. In networking a packet has a lot of overhead, here there is none of that.

k

When you start training/preconditioning the receiver, you won't get much of a recognizable output, maybe half a byte here and there, with or without start or stop bits,...until the receiver is conditioned. Which is why I keep saying you have to train the receiver first and ignore that data, then send some sort of sync byte to get things going.

In this project's case, we don't need much of anything so far, but with data transmission, you'll need to figure out some sort of packet method of transferring data.

The TXPIC (and therefore transmitter) still sends start and stop bits. It's just that the receiver module doesn't care about any start or stop bits. The PIC (rather the program anyways) still sees the start and stop bits and acts on them accordingly (and remember, a start bit is a low, a stop bit is a high, so that's 50% 1's and 50% 0's, they even themselves out, just like they should with manchester encoding). It's the data in between that ends up encoded.
If the PIC SerIn starts to receive a byte in the middle of it, it won't get the right stop bit, and jump out. If the PIC SerIn statement somehow never receives a full 8 bits and a stop bit, same thing, it'll timeout and jump to whatever you tell it to go to.

I don't know how to explain it to you any farther except to tell you to get online like I told you to do awhile back and do some Google'ing on manchester encoding, 433 transmitter/receiver modules, figure out how they work, why they need to use manchester encoding, etc.
The idea really isn't that hard to wrap your head around. And once you figure it out, you'll be all over it.
JDG