[OpenTRV-dev] Puzzling long-term bugs

Jeremy Poulter jeremy at bigjungle.net
Wed Sep 28 17:11:19 BST 2016

Is this more than just UART being UART and the clocks of of each side being

Maybe try repeatedly sending 'U' on one of the problematic devices and
measure the frequency, should be half the baud rate as U is 01010101

IIRC you use a relatively slow baud rate (4800 IIRC) so you could be
overwriting data in a buffer if you send data to fast?


On 28 Sep 2016 3:08 p.m., "Damon Hart-Davis" <damon at opentrv.uk> wrote:

> Hi,
> We have a Wiki page here for our general amusement:
> https://github.com/opentrv/OTWiki/wiki/Puzzling-Long-Term-Bugs
> We’ve certainly been having some puzzlement while putting together a small
> run of valves for a trial over the last few days.  Could be summarised as
> ‘dodgy serial’:
> - Some REV7 and other V0p2 units seem to have problems with serial RX and
> TX, garbling some characters
>     - Seems especially problematic for longer (16+?) blocks of characters
> such as setting a key
>     - Have tried to ensure no sleeping or other fiddling with CPU clock
> during UART operation
>     - Seems to apply to a few % of REV7, REV10 boards at least
>     - It has been possible to load a large (30KB) app over serial with the
> bootloader.
> Any ideas welcome!
> Rgds
> Damon
> _______________________________________________
> OpenTRV-dev mailing list
> OpenTRV-dev at lists.opentrv.org.uk
> http://lists.opentrv.org.uk/listinfo/opentrv-dev
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