techElder
Well-known member
There's a lot of discussion on here about preambles ($55$55 or "UU") with wireless serial comms, but I'm confused about the reception of preambles with wired connections.
I'm using an interrupt driven background hser procedure that works great due to a perfect test connection so its hard to find out what it will do with a lousy connection.
If I send a preamble of "UU", PAUSE, a QUALIFIER/ID and some data, that's exactly what I get in scratchpad memory. Easy to slog through the preamble and process the QUALIFIER with @ptr etc.
However, if the preamble gets partially scrambled, perhaps only receiving "U" and the rest of the packet is accurate, is that a case for abandoning the total packet? Didn't the 1's & 0's pattern of the preamble do its job and sync the hardware? In this case I won't know EXACTLY where the QUALIFIER is in scratchpad memory without scanning for it.
PS. I'm probably over-thinking this again.
I'm using an interrupt driven background hser procedure that works great due to a perfect test connection so its hard to find out what it will do with a lousy connection.
If I send a preamble of "UU", PAUSE, a QUALIFIER/ID and some data, that's exactly what I get in scratchpad memory. Easy to slog through the preamble and process the QUALIFIER with @ptr etc.
However, if the preamble gets partially scrambled, perhaps only receiving "U" and the rest of the packet is accurate, is that a case for abandoning the total packet? Didn't the 1's & 0's pattern of the preamble do its job and sync the hardware? In this case I won't know EXACTLY where the QUALIFIER is in scratchpad memory without scanning for it.
PS. I'm probably over-thinking this again.