[DSP-10] U107 Voltages

Sun, 7 Mar 2004 14:16:55 -0700

Hello Jiro,

No, there is not a software fix for this problem.  Many devices are edge
triggered and want a nice straight edge.  Software alone cannot provide the
edge.  That must come from hardware.

73,

- Steve, N7HPR
 ([email protected])

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Yamamoto Jiro
> Sent: Sunday, March 07, 2004 2:11 AM
> To: [email protected]
> Subject: RE: [DSP-10] U107 Voltages
>
>
> Hello Steve,
>
> Thanks for the detailed description for your solution. I will try it
> when I get another 74HC14. BTW I am also interested in a "software fix"
> instead of a "hardware fix". The idea of the software fix is to modify
> the code in UHFA where a bit pattern is set for each of RF gain. For
> instance, What if '10001000' for RF gain 100 were replaced with
> '01000100'? I don't know if this works or not, but I am just curious.
>
> Jiro JQ2LMG
>
> On Sat, 6 Mar 2004 19:13:03 -0700, Steven Bible wrote:
> > Hello Jiro,
> >
> > The problem comes from the level shifters on the KDSP10 board (the
> > PI5C3245S).  Level shifting takes time, and you see this in your o'scope
> > traces as sloping traces on the Serial Clock (FL2) and Serial
> Data (FL0).
> >
> > My solution was to use an additional 74HC14 DIP and piggy back
> it on top of
> > U3 on the KDSP10 board.  Bend pins 1 through 6 and 8 through 13 pins
> > straight out from the package.  Be careful not to stress the
> pin too much as
> > you bend it, they may break.  Clip off the narrow part of the
> pin and leave
> > the thick part of the pin.  Allow the power (pin 14) and ground
> (pin 7) pins
> > to stay the same, hanging down.  Piggy back the 74HC14 to the
> top of U3 by
> > soldering the power (pin 14) and ground (pin 7) pins to the same on U3.
> > This provides power and groud to the top 74HC14.
> >
> > Connect a wire from P2-4 (FL2) on the KDSP10 to pin 13 of the piggy back
> > 74HC14.  Connect a wire from pin 12 to 11.  Connect a wire from
> pin 10 to
> > the through hole capacitor for FL2.
> >
> > Connect a wire from P2-3 (FL0) on the KDSP10 to pin 1 of the piggy back
> > 74HC14.  Connect a wire from pin 2 to 3.  Connect a wire from
> pin 4 to the
> > through hole capacitor for FL0.
> >
> > I appoligize for only words to describe the above solution.  If
> you like, I
> > can take some photos and post them to a web page.
> >
> > Please let us know if this helps solve your problem.
> >
> > 73,
> >
> > - Steve, N7HPR
> >  ([email protected])
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