[DSP-10] DSP-10

[Steve Bunch]

On May 3, 2013, at 12:22 AM, Bob Larkin wrote:

> Bob, I don't know the answer for those two operating systems.  The DSP-10 has been made to "almost work" under Win XP, using a DOS emulator.  The serial port works, and I believe running through a USB converter should be OK.  But, the issue that came up under XP is all the timing that is done in the PC.  This shows up in many places.  The most obvious is sending CW.  The transmission of each dot or dash, start and finish, is the result of commands sent at the right time over the serial port.  Unfortunately, XP may go off for 100 milliseconds, or more, to do something "really important" leaving the key either up or down.  It gets very tough to copy.

Instead of sending on/off, would it be hard for you to send, say, a count of time-units (length of a unit would be settable) to transmit, and then how many to pause before processing the next character?  That would allow a modest amount of buffering at the DSP-10 side to smooth over burps in transmission time.  Another maybe-easier option is to let the DSP-10 generate the Morse.  It's really easy to do, you just encode the dits and dahs as 1's and 0's in a byte with a '1' added at the end, shift it out and generate dits or dahs until the register has nothing left in it but the stop bit.  Or send straight Ascii and let the DSP-10 look it up in a table.  You lose the sound of the fist, unfortunately, but simplify your life a lot, and it's certainly not demanding from a realtime standpoint.  ;-)

W.R.T. your other email about GTK/Qt.  I haven't used GTK myself.  Qt is a complete environment that abstracts away the OS to a large degree, so it's not that hard to create a Qt application that will run on Windows, Linux, and Macs with a recompilation.  There's a Qt program called "designer" that will generate the UI skeleton for you, and that'd be fairly appropriate for this sort of job.  Basically, you would just have to write the action code that happens when buttons/sliders/etc. are tweaked, and put your signal processing in the main loop.  It's not going to all be copy/paste, but not overly difficult.  The trickiest part to do efficiently is usually the graphics, but Qt does support a good set of graphics operations and implements them fairly efficiently, though for best performance you'll want to use OpenGL and let the graphics card to the hardest work.

My experience with realtime in Linux is that "it depends".  Mostly on the drivers and how you configure it.  But a realtime-priority process on Linux doesn't generally have much trouble getting the CPU any time it wants it - it's usually badly-written drivers that disable interrupts or other realtime processes that would get in the way.  I haven't had any trouble with that, but I was using a peripheral (a USRP) that had some buffering, so your mileage may vary.

FYI, I'm on the DSP-10 list because I almost built one but didn't have time at the time because of work.  Sold the DSP kit to a guy in the UK, and didn't get back into digital radio again until I was nearer retirement -- now I'm working again, and don't have time again.  Sigh.  Life moves in cycles!

73,
Steve K9SRB

> I have had some success with Ubuntu and Puppy Linux, that do not seem to grab large blocks of time.  It has not been fully tested, however, and there may be problems.  I don't know if that would be helpful?  Right now it is on the back burner!!
> 
> 73, Bob
> 
> On 04/15/2013 11:08 AM, wb2srf at juno.com wrote:
>> Enjoy reading the activity I have not used my DSP-10 in quite a while. Does anyone have software that will run on either a Apple or Windows 7 using a USB to serial converter Kind Regards,Bob Johansen
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