[OpenTRV-dev] Bootloader stuggles!

[Stuart Poulton]

Just floating ideas.
On 16 Apr 2013 20:27, "Damon Hart-Davis" <EMAIL ADDRESS HIDDEN> wrote:

> Hi
>
> Fewer parts, less space, and lower power potentially.
>
> Rgds
>
> Damon
>
>
> On 16 Apr 2013, at 20:22, Stuart Poulton wrote:
>
> > 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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