[time-nuts] Hyperterminal with variable baud rate

[Hal Murray]

jimlux at earthlink.net said:
> How far are you from a settable rate?    The whole beauty of asynchronous
> serial is that you can tolerate huge (5-10%) errors in timing

10% is pushing it.  In the simple/common 8N1 case, you have a start bit, 8 
data bits, and a stop bit.  The nasty case is when all the data bits are the 
same as the start bit.  When you get to the transition for the stop bit, you 
have to decide if there were 7 or 8 data bits.  (Well, the UART has decided 
already, you just hope it got the right answer.)  Don't forget to round 
up/down by the asymmetry in rise/fall times.

If there are transitions within the data byte the receiver can resynchronize.

But yes, I agree that the timing can be pretty sloppy.



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