[McHUG] Re: Si570 board question

[n3sb at qis.net]

My SI570 board is running. Getting about 56.320 MHz out of the board on
power-up. A little searching on the yahoo softrock group has confirmed that is
what the board should do. WOOT!!

I have not installed any jumpers at H3 or H4. Just feeding the board 12 VDC.
It's drawing about 80 mils. The regulator holds constant output voltage down to
about 9 Volts input. The SI570 itself will keep working down to about 7 volts
input (to the regulator through R1). For lower voltage input, R1 should be
pulled. Since I have a nice source of 5 VDC on my Arduino breadboards, I'm
going to replace R1 with a wire.

Currently nothing installed at R3 and R4. C6 and C7 are 0.1 uF.

Now it's time to play with some AVR / Arduino software. 

73; Steve, N3SB

Quoting Peter Morton <mortonph at comcast.net>:

> Rich-
> 
> Don't put anything at the R3 and R4 positions.  These positions are tied to 
> ground at one end and to the SI570 outputs on the opposite end.  These parts
> 
> are no longer used and are no longer on the schematic.
> 
> For the SI570 output connection to the SMA connectors:
> 
> If you are using the LVDS version of the SI570, I recommend you use the 0.1 
> uF capacitors supplied at C6 and C7.  The capacitors will provide isolation 
> at the board outputs from the DC voltage present at the SI570 outputs. If 
> you decide to use an LVDS receiver at the receiving end, short the C6 and C7
> 
> positions.  The LVDS outputs only swing about 0.35 volts and ride at a 
> nominal 1.25 volt common-mode DC level.
> 
> If you are using the CMOS version of the SI570, how the output is configured
> 
> depends on what you are driving on the receiving end.  If  you are driving 
> 3.3 volt logic, then use the 49.9 ohm resistors in place of C6 and C7 or 
> short out the C6 and C7 positions.  The resistors provide short-circuit 
> protection and some protection from inadvertent mis-connections.  The CMOS 
> SI570 puts out a square-wave swinging from 0 to 3.3 volts.  If you drive 
> something other than 3.3 volt devices, you may have to use a different 
> output configuration.
> 
> Headers:
> 
> Header H1 and R5 are for the Vc pin of the SI571.  The SI570 does not use 
> this pin.  Nothing needs to be done at H1 and R5.
> 
> H3  is for the OE (output enable) pin of the SI570.  I put a wire jumper 
> between pins 1 (VDD) and 2 of the header H3 to pull this input high.  I 
> subsequently learned that the part has an internal pull-up resistor on this 
> input so no jumper is required (but I haven't tried it without the jumper).
> 
> Good luck.
> 
> -Pete
> 
> 
> ----- Original Message ----- 
> From: "Rich Mitchell" <geobra at att.net>
> To: "Peter Morton" <mortonph at comcast.net>
> Sent: Saturday, March 22, 2008 12:05 PM
> Subject: Re: Si570 board question
> 
> 
> > Pete and Steve,
> >
> > Thanks all, I guess the bevel is in the detail.
> >
> > Followup questions for Si570 board.  Now I have R3, R4 and R5 empty.  I 
> > assume R3 and R4 are where you would put either the  49.9 resistors or 
> > wire if you wanted DC connection.  R5 at 0 should be a wire?? Or just 
> > leave it out and ignore H4, whatever that was for.  H3 is a 3 way header. 
> > What is that used for?  I would guess set it on 1 - 2 to program the Si570
> 
> > and 2 - 3 once a frequency is chosen.  If you are going to be frequency 
> > agile you just leave it on 1 - 2??
> >
> > Thanks
> > Rich
> >
> > --
> > McHUG - Physical Computing ;)
> > MicroController Ham User Group
> >  -------------- Original message from "Peter Morton" 
> > <mortonph at comcast.net>: --------------
> >
> >
> >> Rich-
> >>
> >> The rounded pin (as viewed from the bottom) of the SI570 is pin 1.  The
> >> package should be oriented so this pin is next to the dot on the board.
> >>
> >> The GTL2002 has a beveled edge along the long dimension on top of the
> >> package.  This edge is on the same side as pins 1 through 4.  I couldn't
> >> figure it out either until I downloaded the data sheet.
> >>
> >> -Pete
> >>
> >> ----- Original Message ----- 
> >> From: "Rich Mitchell"
> >> To: "Peter Morton" ; "Steve Beckman" ;
> >> "Steve Beckman"
> >> Sent: Saturday, March 22, 2008 9:21 AM
> >> Subject: Si570 board question
> >>
> >>
> >> > Steve and Pete,
> >> > Been up early trying to build the Si570 board.  Just want to confirm 
> >> > the
> >> > orientation of U2 and U3.  I figure on U2, the Si570, the rounded pin 
> >> > on
> >> > the bottom of the chip corresponds with the hex shaped mark on the 
> >> > board.
> >> > So the printing on the chip is upside down compared to the "U2" on the
> >> > board.  I haven't found the pin 1 indicator on U3.  So is the printing 
> >> > on
> >> > the chip upside down or right side up compared to the printing on the 
> >> > rest
> >> > of the board?
> >> >
> >> > Steve, most excellent box of parts!!!!  By the way, Chuck Coffee 
> >> > describes
> >> > himself as a "AVR nut".  Sounds like one of us.
> >> >
> >> > Rich
> >> >
> >> > --
> >> > McHUG - Physical Computing ;)
> >> > MicroController Ham User Group
> >> 
> 
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