[hpsdr] Gibraltar Prototyping

Thu Jun 8 19:25:16 PDT 2006

Steve,

Right. I haven't looked at the PIC18F4550 Data Sheet for a few weeks, so
I'm refreshing my memory here. 

The chip does have an MSSP - Master Synchronous Serial Port - which can
be configured to support I2C Multi-master mode. This is on PORTB.

I would also suggest we use the 44-pin version, so that we also get the
SPP - Streaming Parallel Port - for USB I/O. This is on PORTD. By my
reading of the Data Sheet, this avoids some of the issues Phil H. is
concerned about, since the USB interaction can be purely interrupt
driven.

[Now I'm getting totally carried away, so it's all likely to get really
silly now.] So, a rough model would be to use the SPP to get USB packets
in and out of a buffer memory, maybe a smallish off chip RAM, then, in
main line outside the ISRs, the CPU reads and writes those packets and
converts them to I2C commands for the CPLD.

My, my, I'll have to go lie down and cool off.

	Chris - AE6VK

-----Original Message-----
From: Christopher T. Day 
Sent: Thursday, June 08, 2006 6:54 PM
To: Steven Bible; hpsdr at hpsdr.org
Subject: Re: [hpsdr] Gibraltar Prototyping

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

Steve,

I think the PIC USB part is a good idea. Full Speed should be fast
enough since we're presumably only doing control and configuration over
USB, and it would make Gibraltar independent of Oxy or anything else.
However, it might be worth some thought about getting such control also
from Ozy if there is one in the Atlas box. I seem to recall that the
RefLock II - _I_ have one anyway - has an I2C connector hooked up to
some CPLD pins. That would be an obvious way to do this if the PIC USB
chip controlled Gibraltar over that I2C. We can use the fact that I2C is
multi-master.

And, through the generosity of Eric E., I have his PICDEM FS USB
development board for that very chip. Hmmm, sounds like I have all the
bits for a breadboard version of this, doesn't it? Plus Quartus, of
course.

	Chris - AE6VK

-----Original Message-----
From: Steven Bible [mailto:n7hpr at tapr.org] 
Sent: Thursday, June 08, 2006 6:38 PM
To: hpsdr at hpsdr.org
Subject: Re: [hpsdr] Gibraltar Prototyping

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

Hello Phil,

Roger all.  I'll be using the C18 compiler.

The idea is to add some flexibility to Gibralter as ideas come flooding
in
:-).

73,

- Steve, N7HPR
 (n7hpr at tapr.org)

> -----Original Message-----
> From: pvharman at arach.net.au [mailto:pvharman at arach.net.au]
> Sent: Thursday, June 08, 2006 6:12 PM
> To: Steven Bible; Steven Bible
> Cc: hpsdr at hpsdr.org
> Subject: Re: [hpsdr] Gibraltar Prototyping
>
>
> Hi Steve,
>
> That sounds like a good plan. I started to use the 18F4550 as a
> way of getting
> an A/D to USB converter going but because of all the problems I
> ended up using
> the FX2 and FPGA.  The 18F4550 does work OK but be aware of a couple
of
> things.
>
> 1. You need to run all your code in a state machine so you
> frequently service
> the USB hardware.
> 2. If you intend to use the USB function of the 18F4550 then check the
C
> compiler support. I strongly suggest that you avoid the FED
> product, that is
> what I tried to use and it was full of bugs.
>
> 73's Phil...VK6APH
>
>
>
>
>
> Quoting Steven Bible <srbible at earthlink.net>:
>
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > As Bob has already aluded to, all these techniques have the
> same pricinples
> > involved.
> >
> > I've started on Gibraltar and for first pass I was planning on
> the Reflock II
> > design with the iLotus M12M and Trimble-T GPS footprints, and
> for OCXO, the
> > Crystek and Valpey-Fisher footprints.  This way we can
> experiement with each.
> >
> >
> > I could also include a microcontroller on the PCB for added
> flexibility.  I
> > would suggest the PIC18F4550 full speed USB microcontroller.
> >
> > - Steve N7HPR
> >
> >
> >
> >
> > -----Original Message-----
> > >From: "Christopher T. Day" <CTDay at lbl.gov>
> > >Sent: Jun 8, 2006 10:27 AM
> > >To: Lyle Johnson <kk7p at wavecable.com>
> > >Cc: hpsdr at hpsdr.org, FRANCIS CARCIA <carcia at sbcglobal.net>
> > >Subject: Re: [hpsdr] Gibraltar Prototyping
> > >
> > >***** High Performance Software Defined Radio Discussion List *****
> > >
> > >Exactly. That article has been in my pile for some time. I
originally
> > >had thoughts of combining the Crystalizer kit, the Antenna Analyzer
> > >Temperature control for same, Shera's GPS stabilization
> technique and my
> > >cheap Delua GPS module with a 1PPS output, just to see what one
could
> > >wind up with. However, I've been too distracted by other things so
far.
> > >[What I just described sounds a lot like a cheapo Gibraltar,
doesn't
> > >it?]
> > >
> > >
> > >	Chris - AE6VK
> > >
> > >
> > >-----Original Message-----
> > >From: Lyle Johnson [mailto:kk7p at wavecable.com]
> > >Sent: Thursday, June 08, 2006 10:21 AM
> > >To: Christopher T. Day
> > >Cc: FRANCIS CARCIA; hpsdr at hpsdr.org
> > >Subject: Gibraltar Prototyping
> > >
> > >> I would suggest that the RefLock II could be used as a Gibraltar
> > >> prototyping system similar to the way PhilH and Bill have been
using
> > >the
> > >> Xylo board for prototyping Janus.
> > >
> > >Consider also some of the techniques employed in the GPS oscillator
> > >stabilization system designed by Brooks Shera
> > ><http://www.rt66.com/~shera/index_fs.htm>
> > >
> > >73,
> > >
> > >Lyle KK7P
> > >
> > >
> > >_______________________________________________
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> >
> >
> > \r\n- Steve\r\n  (n7hpr at tapr.org)\r\n
> > _______________________________________________
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> >
>
>
>

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