Re: [Simulavr-devel] more info on serialrx/feedback issue

[address@hidden]

On Thu Apr  9 11:30 , Joel Sherrill  sent:

>I did one run where I printed the baudrate out in
>step and it is always 9600.  This appears to match
>the value I hand calculated for Ubrr based upon
>a cpu frequency of 4000000.
>
>OUT 0x09, R24 Ubrr=0x19
>
>The value of timeToNextStepIn_ns in the SerialRX::Step
>method is computed 1e9/baudrate/16 and always has one
>of the following values.

>From this formula, the sample rate is 16 times the bit rate.
Unless SerialRX using best 9 out of 16 or something,
that is too fast.

>+ 6510 ns
>+ 45570 ns (skip 7)
>+ 91140 ns (skip 14)
>
>I know the UART internally is using a by 16 divide but
>if SerialRX is reassembling the bits based upon the "real
>timing" of a RS-232 transmission, then isn't that math
>wrong?  9600 baud is ~ 1 character a millisecond.  Is
>the Step method sampling too fast?

--
Michael Hennebry
address@hidden
"War is only a hobby."

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