[hpsdr] [FPGA_USB] PCB Design

[Eric Ellison]

Lyle

I agree completely. We pretty much discussed what we wanted off the
Lionheart to the outside world, but have had little discussion regarding
Phil's board. Not that Phil's board is 'bad' or short on anything. We have
just been discussing other things. I don't see the need for the extra gpio.
We also can't afford or even need a board to board daisy chain.

We wouldn't have both the 68 pin DIN, one or the other. 


If we DO decide we want 64+ pins out of the enclosure, from the fpga board,
several things are obvious.

1. We will need a High Density connector like HD scsi
2. We will need an external daughter card attached to a SCSI umbilical for
everything except for USB and perhaps Serial using an RJ45 or something, on
board. (NOT DB9).
3. Cost, inventory, and difficulty go up!

So what do we need coming to the outside world?:

Label		Pins			Connector Style	SPACE mm	Need
it?

GPIO 		20			?
Leds		5			?
ClkIn1	2
ClkIn2	2
Clk6/7	2
ClkOutx	2
ClkOuty	2
Serial	8
USB		4
JTAG		10
Byteblaster 10
I2C		?			?

IMHO - if this were stand alone I could understand all the I/O clocks etc.
However this is the heart which should essentially use the bus and should
not require an umbilical or daisy chain. We just need the USB and
programming ports, as well as a couple of LVDS inputs as previously
discussed. Lets start with the high priority connections to the outside
world until we 'fill the lower edge' (outside world), and throw the rest
away. Substitute miniature conectors if necessary.

Comments:?


What do we REALLY need?


Eric


	





-----Original Message-----
From: Lyle Johnson [mailto:kk7p at wavecable.com] 
Sent: Monday, April 24, 2006 10:47 AM
To: Eric Ellison
Cc: 'H. Gruchow'; hpsdr at hpsdr.org
Subject: Re: [hpsdr] [FPGA_USB] PCB Design


> The one thing we must have on the 'outside world' edge of the board is the
b
> type USB connector, since this IS the connection to the PC. My thinking is
> to use a 68 pin HD SCSI connector, which I think should allow us the room
> and an commercial umbilical cable to come off to an external breakout
board,
> I think the connectors are readily available, and commercial cables are
also
> available.
> 
> Dunno.... there is a lot coming off this board! (smile)

I'm getting really confused. I thought the majority of what came off the 
board went to the ATLAS backplane.  We only needed a couple of 
connectors or controls to the "outside world" - DE-9, USB, LEDs, encoders...

A 96-pin backplane plus a 68-pin SCSI connector plus a 64-pin DIN 
connector plus a USB connector on a 4" square board -- where do we put 
the parts? :-)

73,

Lyle KK7P


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