Thanks John, that's great information. How is the KRC2 receiving the band data?
Via the AUXBUS?
Thanks,
Fred
(And thanks Ian for:
"The manual says (on page 25 of rev C):
"The remaining four drivers, labeled A, B, C and D, are TTL-compatible
inputs or outputs depending on the operating mode. In normal KRC2 or
analog modes, the terminals are outputs. In digital parallel input
mode, they become inputs, and receive the BCD-encoded band data."
It doesn't specify that the output format is BCD, but I can't imagine
what else it would be...
73,
~iain / N6ML
"
Fred Cady
fcady at ieee dot org
From: John D'Ausilio [mailto:[email protected]]
Sent: Monday, July 01, 2013 8:42 AM
To: Cady, Fred
Subject: Re: [Elecraft] KE7X KRC2 app note
Hi Fred .. I beg to differ with you re: BCD outputs from ABCD terminals. Absent
any overriding configuration (like analog inputs), the ABCD terminals do in
fact output BCD band info. I know this because I've been using those outputs to
drive my microwave LO synthesizer for the last 4 years :)
de w1rt/john
On Mon, Jul 1, 2013 at 9:24 AM, Cady, Fred
<[email protected]<mailto:[email protected]>> wrote:
Hello all,
Well, the KE7X KRC2 app note is yet another unfinished project I need to get
back on.
The KRC2 is a great little decoder box with tremendous flexibility in how you
use it but it does require you to carefully study the schematic. Here are some
of my more-or-less random observations. I hope to put these into a more
cohesive form one of these days (soon).
KRC2 Outputs:
The KRC2 outputs can be used in high-side driver applications (where the
external device needs + voltage) or low-side drivers (where the external device
needs a signal pulled to ground). The KRC2 can do both simultaneously. Note
that the high-side driver supplies +12 V when asserted but is NOT pulled to
ground when it is not asserted. Similarly, the low-side drivers are not pulled
up when not asserted.
There are 16 high-side and 16 low-side outputs. You can map them anyway you
like (even to do a BCD output) but note that the mapping will be the same on
the high-side and the low-side.
Although there isn't a native BCD coded output, you can make one by using the
low-side drivers and supplying the needed pull-up in your external device
(which is the way those devices should be designed anyway, but that's another
story).
Using the AUXBUS:
As others have mentioned, the best way to use the KRC2 with the K3 is to use
the AUXBUS output on the K3's ACC connector. A caveat is, like the KAT500, the
KRC2 must be powered-up before the K3. If it isn't, the K3 will just sit there
with a blank screen when you turn it on. That's very scary when it happens to
you the first time! The reason that happens is that the KRC2 seems to load the
AUXBUS down when it (the KRC2) is not powered-up. I'm not sure I understand
why. Bottom line: Turn the KRC2 on first and keep it power-up.
Using the Serial Port:
Be very careful if you go this route. The problem is that the KRC2 was designed
to use the K2's serial port, which if you recall, is a non-standard RS232
interface. If you connect the KRC2 to a standard serial port with the standard
RS232 signals RI, CTS, RTS, DSR, and DTR, AND with the KRC2's jumpers W11-W15
connected you could (and probably will) damage the KRC2. Don't ask me how I
know that. When jumpers W9, W10 and W22 are installed, the KRC2 can pass K3
serial data on to a PC, for logging or other operating. If you want to do that,
the K3's serial data must be 19.2 Kbaud. I haven't played with this mode enough
to see how the P3's baud rate fits into the whole scheme.
Using the BCD Input:
The K3 does put out BCD band data on the ACC jack and this can be used with the
KRC2. I don't see problems with this approach other than the known problems
associated with the K3's internal pull-ups that limit the loading it can drive
on the BCD outputs. I think the KRC2 will work OK but you might not want to
have other loads from other decoders on these signals. I have yet to play with
this mode.
Jack Brindle is a great and friendly resource for questions on the KRC2.
I'll get back onto this writing project one of these days as it gets warmer in
MT and I take refuge in the coolness of my basement shack.
73 and cheers,
Fred KE7X
Fred Cady
"The Elecraft K3: Design, Configuration and Operation 2nd Edition"
"The Elecraft KX3 - Going for the Summit"
www.ke7x.com<http://www.ke7x.com>
Also available at www.lulu.com<http://www.lulu.com> (possible discount code
JULYBOOKS13)
fcady at ieee dot org
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