[OpenTRV-dev] Bootloader stuggles!

[Kevin Wood]

Yes, that's what I meant to say, actually. Not necessarily accuracy of the
clock, but inability to hit a "standard" BAUD rate accurately enough.

> 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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