[Xastir] Soundmodem

[Dale Seaburg]

On 7/27/2011 11:00 AM, Andrew Errington <a.errington at lancaster.ac.uk> wrote:
> On Tue, 21 Jun 2011 22:54:38 Andrew Errington wrote:
>> >  I am pleased to say that my code for driving PTT with a GPIO pin on a USB
>> >  audio chip has been incorporated into soundmodem v0.16.  Currently it
>> >  compiles for CM108 and other C-Media chips, but I have a patch which will
>> >  allow the vendor IDs and product IDs for SSS1621 and SSS1623 audio chips to
>> >  be recognised.
>> >
>> >  I have tested it with the diagnostic functions (PTT test button) in
>> >  soundmodemconfig, but it should work 'for real'.
> I am further pleased to announce that I have successfully sent messages
> between two instances of Xastir connected to two instances of soundmodem
> connected to two USB audio devices connected to two radios (Yaesu VX2r and
> Yaesu FT-7100M).  The devices were connected to the same laptop, but they are
> conceptually separate.  The antennas were only about a metre apart.  My test
> was brief, but I believe it will work consistently.
>
> I used two USB audio dongles based on SSS1623 with a PTT transistor added.  I
> discovered that SSS1623 needs a pull-down to stop the transistor being turned
> on when the device is plugged in.  SSS1623 has a pull-up on GPIO, CM108 has a
> pull-down.  Grr!  Obviously it's not a problem once soundmodem is running.
>
> I also recently bought another USB audio dongle with an epoxy-blobbed chip.
> The chip is SSS1623, but the GPIO pins are not bonded out and not
> accessible.:(
>
> 73,
>
> Andrew
> ZL3AME
>

Andrew,  excellent work!  Do you remember where you got the USB audio 
dongles that had the GPIO pins exposed - non-epoxy blobs?  The ones I 
have are the SSS1623 die with the epoxy blob.  Perhaps only the latest 
are the ones with the epoxy blob - cheaper to make.

Dale - KG5LT