[time-nuts] WWVB teensy BPSK early experiments

Sun Nov 15 07:52:22 UTC 2020

Hello Time Nuts/Paul,

Yes - I know you have said that - the point was/is I wasn't sure there was
something in the code or not that could be calling some of the
touch screen functions - if you said you scrubbed that and I didn't
understand - thanks for doing that.

I was wondering - using the Stormwise antenna in inductive coupling mode -
I got at least one good decode cycle - but the TFT/Teensy
evidently froze - I wasn't getting the serial port dump - the Teensy
appeared to be locked up - no LED blinks, etc:

https://user-images.githubusercontent.com/2308903/99171441-ee159b80-26bd-11eb-8b1f-062ce90a1265.jpg

Good news is that evidently at least one good decode cycle took place (CH
code) or maybe it was in the process of completing one good decode cycle.

73's,
John
AJ6BC

On Fri, Nov 13, 2020 at 10:40 AM paul swed <paulswedb at gmail.com> wrote:

> John I mentioned in an earlier post the touchscreen is not used and there
> is nothing in the code that I see. I have no wires connected. Display is
> stable.
>
> On Fri, Nov 13, 2020 at 11:09 AM John C. Westmoreland, P.E. <
> john at westmorelandengineering.com> wrote:
>
> > Hello Time Nuts,
> >
> > Paul, the wiring harness I made is longer than 6" - not by much - but
> I'll
> > shorten those and see if it clears it up.
> > I thought the same thing - maybe the display could be flaky - or maybe
> > strange things can happen too if in
> > the software the touch screen part is enabled but the wiring isn't there
> -
> > not sure.  But, can't rule that out right
> > now - will double check to see if in the code the touchscreen part is
> > running or not.
> >
> > I'm also checking the CHIP_MIC_CTRL register in my code - I wanted to see
> > if disabling the micbias block could work -
> > the register can be written/changed - in the control_sgtl5000.cpp file -
> in
> > the micGain() function -
> > change:
> >
> > return write(CHIP_MIC_CTRL, 0x0170 | preamp_gain)
> > to
> > // return write(CHIP_MIC_CTRL, 0x0070 | preamp_gain)
> >    // attempt to disable mic bias block --- aj6bc/jcw
> > or
> > return write(CHIP_MIC_CTRL, 0x0000 | preamp_gain)
> >
> > If you want to read that back - then:
> > in control_sgtl5000.h - move:
> >  unsigned int read(unsigned int reg); // removed from protected:
> >
> > from protected to public:
> >
> > and in your code you can call something like:
> > // check value of mic control register:
> >   mic_ctl_regval = sgtl5000_1.read(CHIP_MIC_CTRL);
> >   Serial.printf("\r\nMic Control Register (ADDR 0x002A) = 0x%x \r\n",
> > mic_ctl_regval);
> >
> > you may need to:
> > #define CHIP_MIC_CTRL      0x002A // microphone gain & internal
> microphone
> > bias
> > at the top of your file.
> >
> > I'm still not sure if that's OK to do - I think the chip is looking for a
> > feedback on that possibly and it doesn't really buy you much.
> > I'm still testing all of that now - maybe just being able to read that
> > register back is worth something.
> >
> > I received the antenna from Stormwise and am using in an inductive
> coupling
> > mode with the Teensy set up - and I got the first
> > successful decode using the code from Chris Howard - so good job there
> > Chris.  Gotta admit it's pretty cool watching the inductive
> > coupling effect work.
> >
> > It's apparent I still have some noise - I haven't done a lot yet for
> > shielding anything, so I obviously need to do that - good news
> > obviously is finally seeing some good decodes coming in.
> >
> > Of course, this is in the quiet wee-hours but WWVB is pretty strong at
> this
> > time at my QTH.
> >
> > I'll work on ways to reduce noise next.
> >
> > 73's,
> > John
> > AJ6BC
> >
> >
> >
> >
> >
> >
> > On Wed, Nov 11, 2020 at 12:21 PM paul swed <paulswedb at gmail.com> wrote:
> >
> > > I kind of wonder if you don't have a flakey display. I did not add the
> > > terminating R and everything has always worked fine on the display.
> > After I
> > > quit using the 3" jumper cables to the audio card and stacked the
> > modules,
> > > the audio worked correctly.
> > > My display is on a set of 6" jumpers and has been stable from day one.
> > > Though currently the display isn't connected since I am experimenting
> > with
> > > various modules in the teensy.
> > > Regards
> > > Paul
> > > WB8TSL
> > >
> > > On Wed, Nov 11, 2020 at 10:47 AM Graham / KE9H <ke9h.graham at gmail.com>
> > > wrote:
> > >
> > > > John:
> > > > I suggest you try Chris Howard's
> > > > https://github.com/chris-elfpen/Teensy4WWVBsdr
> > > > You might have to adjust the I/O pins for Teensy 4.1 vs 4.0
> > > > I am having no problems with the display once I put in the source
> > > > termination resistor.
> > > > Been running for multiple days, so far.
> > > > --- Graham
> > > >
> > > >
> > > >
> > > > On Tue, Nov 10, 2020 at 9:45 PM John C. Westmoreland, P.E. <
> > > > john at westmorelandengineering.com> wrote:
> > > >
> > > > > Hello Time Nuts,
> > > > >
> > > > > I've been running some tests - I just had the screen 'white-out'
> > > problem
> > > > > happen again - I have a termination resistor on the SCK line (pin
> 13
> > on
> > > > the
> > > > > Teensy 4.1) -
> > > > > so it appears this is related to the TFT screen updates - maybe a
> > pixel
> > > > > write going out of bounds.  The Teensy is still running - but the
> > > screen
> > > > > can't be read.
> > > > >
> > > > > Note the current code I'm testing is here in case anyone is
> > interested
> > > -
> > > > > it's from the PJRC forum:
> > > > > https://github.com/jwestmoreland/el_supremoWWVBsdr
> > > > >
> > > > > 73's,
> > > > > John
> > > > > AJ6BC
> > > > >
> > > > >
> > > > >
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