[hpsdr] What can we do with 2 cards

[Eric Ellison]

Bill et.al.

This is a really good point, and is indeed how this all started with my
simple 'e-mail' list of folks interested in the Xylo Project. I don't think
we should lose sight of these objectives. Nor do I think we should 'short'
any of the other project boards which have come forth as a result of the
buss structure. Indeed it is how you and Phil are using the Xylo board
without Atlas.

Hang me for heresy! 

I suggested the buss structure even back in the PIC project as a way to add
distributed features without duplicating effort and keeping hardware in
'logical' blocks. It also allows for a great testing ground. However the
opposite is true. The buss is just an extension to merge 2 or more circuit
boards. At the rate which Lyle, Phil_C and others seem to be able to
reconfigure and update PCB and schematic layout and design. I would propose
that this 2 board Universal Station Accessory, once proven (which you have
essentially already done) be merged into a single board product for the
SDR-1000. Even Gerald might want to be involved in that. I think sales have
been very good and there are probably 1000 or more 1000's out there.
Obviously there are some differences in layout when if this is done, but I
don't think they would be that major. The Janus in it's current proposed
state is still also needed for the Mercury etc.

I think there are a number of examples and possibilities like this after
they are evolved on the Atlas. The Gibralter is probably a good example of
something which could be 'merged' in this way.

Dunno, but I agree with your RFC here! Perhaps we can discuss fundamentals
like this if we get enough show up on Teamspeak tonight.

Thanks
Eric

-----Original Message-----
From: hpsdr-bounces at hpsdr.org [mailto:hpsdr-bounces at hpsdr.org] On Behalf Of
Bill Tracey
Sent: Saturday, May 13, 2006 2:26 AM
To: HPSDR List
Subject: [hpsdr] What can we do with 2 cards

***** High Performance Software Defined Radio Discussion List *****

When we started down this path with the Xylo I think one of the 
configuration goals we had was:

         1. Sound Card replacement
         2. Ultra Low Latency CW input
         3 .SDR 1000 Parallel Port Control

As we morphed to HPSDR my hope was that this configuration could be done 
with two cards - Audio (Janus) and USB/FPGA (Ozy)

At the moment it looks like we may only be able to do #1 with 2 cards.  We 
might be able to do #1 & #2 if we can get low latency CW keying via I2C I/O 
via FX2.    We certainly cannot do #3 with just 2 cards.  At the moment on 
the Xylo prototypes we've got PTT/DOT and DASH coming thru FPGA pins and 
their state gets integrated into the audio data stream going to the radio, 
giving very low latency..  Doing CW via I2C via FX2 may have sufficiently 
low latency, not sure of this.  I'd assume we'd have to read from an FX2 
USB endpoint to get the status of the ports -- anyone know if one can do a 
blocking read waiting for the state of the I2C ports to change from the PC 
-- hate the idea of having to poll the USB port at a hi rate for good CW 
performance.       I don't think we can do SDR 1000 parallel port control 
with the I2C expander as it takes 17 (D0-7, C0-3, S3-S7)  lines, also not 
clear to me  how quickly we can and need to wiggle those lines to program 
the DDS in the SDR 1000 when going via an I2C.

One idea to get back to doing dot/dash directly thru the FPGA is to go 
through the Janus.  It looks like there are 4 unused I/O on the Janus 
CPLD.  Could we add some protection circuitry on the Janus to 2 of those 
lines and configure the CPLD to put those sigs on the Atlas bus.   Maybe 
add 3 more pins to the 0.100 unbalanced audio connector?

I that's not  viable, is there space for protection circuitry for 2 lines 
on the Ozy  and a 3 pin connector?  Could we jumper the configuration of 
the FPGA serial port such that it's either tied to the level converter or 
the external connector?

Just some late night thoughts -- trying to find a way to get a little more 
function into a 2 board setup.

Regards,

Bill (kd5tfd)




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