[time-nuts] WWVB teensy BPSK early experiments

[paul swed]

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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