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sylvandb / gruvin9x

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V4 / Hardware PPM -- pulse polarity cannot be changed #52

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago 
What steps will reproduce the problem?
1. Hook PPM out up to a scope
2. Watch it for a good five minutes
3. Not that the polarity swaps from neg to pos or vise versa, just now and then 
... staying there until the next 'random' swap occurs.

NOT GOOD

Original issue reported on code.google.com by gru...@gmail.com on 5 Oct 2011 at 12:23

GoogleCodeExporter commented 8 years ago 
I should note that this was seen under emulation, not on a real world scope. So 
far, I've not witnessed it happening on the real world scope, which does tend 
to make a lot more sense. I'm going to monitor it for a good half hour though, 
out the corner of my eye.

MEANWHILE, the V4/frsky code (and probably the HARDWARE_PPM mod code) currently 
does not allow the polarity to be changed. So, POS and NEG (model SETUP screen) 
both result in positive polarity.

Original comment by gru...@gmail.com on 5 Oct 2011 at 4:36

GoogleCodeExporter commented 8 years ago

Original comment by gru...@gmail.com on 5 Oct 2011 at 4:37

GoogleCodeExporter commented 8 years ago 
OK -- this fault has been thoroughly tested on a real scope and been found to 
be INVALID.

However, the problem of not being able to change the polarity in the model 
SETUP menu still existed.  I've updated this issue's summary to read "... 
cannot be changed."

That turned out to be because we do not have access to read the status of the 
PPM OUT (OC1B) pin when is connected to the waveform generator, even though we 
can do that on the older ATmega64A chip (according to Vincent, I have not 
personally tested it yet.) So I re-wrote the hardware PPM code the way I 
originally thought of doing it, to now ensure the correct, selected polarity is 
output. Tested OK.

I'll leave this issue open until I've tested that the PINB read actually does 
work on the '64A.

Original comment by gru...@gmail.com on 5 Oct 2011 at 6:58

GoogleCodeExporter commented 8 years ago 
Yup. It works. Issue closed.

Original comment by gru...@gmail.com on 30 Dec 2011 at 2:25