[OpenTRV-dev] Bootloader stuggles!

[Stuart Poulton]

Is there some merit in still using a xtal, rather than relying on the
internal osc?
On 16 Apr 2013 16:25, "Damon Hart-Davis" <EMAIL ADDRESS HIDDEN> wrote:

> But I'm assuming that this bootloader I'm using will end up running at
> 7200 * clockMHz, eg 115200 baud at 16MHz, unless I somehow get it rebuilt.
>
> Anyhow, I'm having fun with power management (at 8MHz) at the moment, so I
> can come back to this issue later.
>
> Rgds
>
> Damon
>
>
> On 16 Apr 2013, at 16:17, Mike Stirling wrote:
>
> > The main issue I have found with serial and the internal RC is that,
> accuracy aside, it isn't an ideal frequency for generating standard baud
> rates. Those FTDI cables will work at obscure baud rates as well, and this
> may work better. For example, I have the serial port on my sensor boards
> working reliably at 500 kbps with the internal RC set to 4 MHz.
> >
> > Mike
> >
> > ----------------original message-----------------
> > From: "Kevin Wood" EMAIL ADDRESS HIDDEN
> > To: "Closed list for developer discussions"
> EMAIL ADDRESS HIDDEN
> > Date: Tue, 16 Apr 2013 11:36:36 +0100
> > -------------------------------------------------
> >
> >
> >> I've had fun and games with serial ports on the internal RC oscillators
> >> before on some AVRs due to the (in)accuracy of the clock. It's not too
> bad
> >> if there are spaces between bursts of characters so the UART can re-sync
> >> but, if you're blasting data at it continuously, bear in mind that it
> can
> >> go out of sync eventually. Maybe now the baud rate is lower that's
> what's
> >> happening?
> >>
> >> Might be better from a point of view of removing barriers to people
> >> playing with the code if they don't have to first mess about with a
> >> non-standard boot loader? Just depends what the cost is in power
> >> consumption.
> >>
> >> Certainly, it ought to be straightforward to make any OpenTRV source
> code
> >> agnostic to the clock speed to keep that option open.
> >>
> >> Kevin
> >>
> >>> For a laugh have a look at:
> >>>
> >>> http://arduino.cc/forum/index.php/topic,160647.0.html
> >>>
> >>> I suspect that I have to build a specific bootloader .hex file set for
> >>> 1MHz and 9600 (or 4800, just to be super PICAXE compatible!) baud
> serial.
> >>>
> >>> Not sure how to do that yet.
> >>>
> >>> May give up for the moment and do the 8MHz version (RC internal osc,
> but
> >>> no divider) to at least flex some other muscles!
> >>>
> >>> Rgds
> >>>
> >>> Damon
> >>>
> >>> _______________________________________________
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> >>>
> >>
> >>
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> >
> > --
> >
> >
> >
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