Si570 Group Buy

 Last Update 07/08/2008

 
SI570 group buy by KM5H Tom Hoflich

Status

PayPal the appropriate U.S. funds to KM5H at Yahoo.com  

 Start-up frequency 56.32 MHz

Si570BBC000141DG LVDS 20ppm Si570CAC000141DG CMOS 50ppm
QTY

1                                      $22                                                   $20
2                                      $41                                                   $37
3                                      $60                                                   $53
4                                      $79                                                   $70
5                                      $98                                                   $87
6                                    $117                                                $105
10                                  $193                                                $170

Add one dollar per order for DX addresses
Lead time is up to 6 weeks

NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW

 USB-Controlled Synthesizer for Softrock RXTX and Local Oscillator Applications Kit

CMOS $37,  $23 without Si570

LVDS $40,  $24 without Si570

Add one dollar per order for DX addresses(Canada in this case)

 

 STATUS

(July 17, 2008)

The price of the LVDS kit (w/o Si570) is $23 instead of $25.

 (July 13, 2008)

Pricing available for USB-Contorlled Synthesizer kits.

 (July 12, 2008)

 All Si570's have been shipped.  More are on order.

I will be shipping the SDR-kits in the US and Canada.

Watch for details soon

See:  http://www.sdr-kits.net/

(July 2, 2008)

 All Si570 orders have been shipped (or will be in the next couple of hours).

I have 4 CMOS left that can be shipped quickly.

New orders will "collect" until I have close to 25 for a new order.

Thanks and 73, Tom KM5H

 (June 24, 2008)

I have received my latest shipment of both CMOS and LVDS versions of the SI570.

All of the domestic orders are packaged and will go in the mail tomorrow.  I am working on the DX orders now and they will go in the mail soon.

I ordered some extra again this time so now is a good time to order and get them quickly.

73, Tom KM5H

 (June 1, 2008)

All of the May orders have been shipped and the June list has started. I will post that soon. Thanks for the DX reports of when you receive your parts.  I am surprised at how quickly some arrive.

Thanks to all

73, Tom KM5H

(May 10, 2008)

First, I want to thank you for all of the "thank you" notes and the DXers letting me know that you received your parts.
Yesterday afternoon, the CMOS parts came in. Avnet sent them overnight since the messed up the order.  So I was able to get them out this week rather than next week.
All of the paypal domestic orders are going into today's mail.
DX and non paypal orders will go in the mail Monday morning since I need an open post office.

Thanks to all
73, Tom KM5H

(May 8, 2008)

I just got notice that the CMOS parts which are shown in the current list on softrockradio.org.si570 will arrive next week and will be in the mail by next Thrusday or Friday at the latest.

73, Tom KM5H

(APR 27, 2008)

Good news. By Tuesday, I should receive enough LVDS parts to fill all orders that I have thru today.  I will  be getting those in the mail as fast as possible.
Unfortunately Avnet messed up again and it will be a little longer for the CMOS parts.  I will let you know when I have some information. I only publish information when I get the FedEx tracking information.

Thanks for your patience.

73, Tom KM5H

 

 (APR 12, 2008)

Yesterday I received 70 CMOS parts. They are all packed. Those that don't require a trip to the post office will go in the mail today.  Those that have to go to the PO will be mailed Monday morning.
I have 50 CMOS on order and 57 orders and 40 LVDS on order and 44 orders so it looks like I will be planning another order when the orders get to 25.

Thanks, Tom KM5H

 (MAR 30, 2008)

 I am preparing another order to go in tomorrow so if you are lurking in the shadows, now is the time. Lead time is still 4 to 6 weeks.
All 25 LVDS on order came in last Monday. But only 10 of the CMOS came in. They have all been mailed to you. I expect balance of 70 CMOS to come in the next two weeks.
Thanks for you patience.

Tom KM5H
 

(MAR 13, 2008)

This week, the last order came in and most have been shipped out.
The few left will go out no later than tomorrow.
See http://www.softrockradio.org/si570
I am preparing the next order for both versions.
It will go in later this afternoon. Any orders that come after this afternoon will be in the next order.

Thanks to all.
Tom KM5H
 

(MAR 8, 2008)  

I had paid orders for 85 CMOS parts so I ordered 90. The 90 will be in on Tuesday and I will get them out as quickly as possible.
I already have enough for another CMOS order which I will do on Monday.
If you want to be included and have not yet paid, please do you paypal before Monday afternoon (CDT).  We got lucky this time because lead time is usually about 4 weeks.
Thanks
Tom KM5H

(FEB 27, 2008)

The order has been submitted.

Anything coming in now will be in a future order.

Tom KM5H

 (FEB 25, 2008)

I have shipped all of the chips on hand.

Tomorrow, I will place an order for both versions of the chip.

73, Tom KM5H
 

  ( FEB 23, 2008)

I have shipped the backlog of 400 Si570's.
I really appreciate all of the "thank yous" and kind words from all of you who have received your parts in the last few days.
I am working on the last shipment of 25 and will have those out soon.
Most of the orders for the last few days have been for the CMOS version I believe mainly because of the announcement of the very neat XTALL.  But, there has been a lot of progress on ways to interface the LVDS version.
It is time to send an order for more LVDS chips. If you are interested, get your payment in soon so you don't have to until the next order.

Thanks to all
73, Tom KM5H
 

(FEB 17, 2008)

 290 are in the mail.  Some of you have already received them.  I have about 40 more packaged and ready to go to the post office (which is closed Monday). Another way of putting it is that orders thru Jan 2, 2008 are on the way to you.

73, Tom KM5H

  (FEB 14, 2008)

The 300 Si570's finally arrived. it turns out that they were marked leaving the factory 12/13/2007 so they were the origial order. Wonder where they were for the last two months. Anyway all of the order one are at the post office as of this morning (some yestersay).
I will start working on order 2 today.
73, Tom KM5H

  

(FEB 10, 2008)      

 Good News!!           FedEx tells me that they will deliver the illusive 300 Si570s on Tuesday afternoon. So, I will get a bunch of them in the mail on Wednesday. I will get all of them out as soon as possible. I figured at 3 minutes per shipment, it will take 8 hours so I ask a little more patience from you.  Thanks
Tom KM5H

(FEB 3, 2008) 

The latest buy is up to 22 so I am going to send the order for 25 today.
I am still expecting 100 in to arrive in about two weeks.
Thanks for your patience.

73, Tom KM5H

  

(JAN 27, 2008)

I received 25 Si570's and packaged them to be shipped tomorrow.
So look for an S in the ship column at softrockradio.org.si570.
Next shipment in 3 week.

73 Tom KM5H
 

(JAN 22, 2008) later

  I finally got a commitment from Avnet.  300 parts will arrive in Phoenix on Feb. 20 and then on to me in a couple of days.  Then on to you in a few days.  This is where it gets wierd.  The seem to have found 25 and I should get them in a few days. I will get those out as soon as I get them.  Where did they get 25????? I am guessing that someone messed up really bad and they don't want to admit it.  More news when I actually get them.
The current order is now full and there are 2 into the next order of 25.

Thanks for all of your patience. 73, Tom, KM5H

   

 (JAN 22, 2008)

The current group of 25 has only 3 openings. I already ordered it.
The demand has slowed. I will take orders for another 25 with the understanding that I will refund those if we do not get to 25. But, I am guessing that when we get the lost 300 into your hands, the demand will increase.
About the lost 300, I was on the phone yesterday about that.  I will be on the phone every day until I get some clear information to report to you.

(JAN 14, 2008)

First, I would like to thank you for the "thank you"s and kind words for my efforts. I really appreciate it.
Second, the orders just keep coming even though I closed Buy 4. So, I am extending that buy to include as many as possible.
Again, you can check Softrockradio.org/ to see what is happening with your order. It is always up to date within 24 hours.
Third, for the last three weeks I have been getting the run-around from the order clerk at Avnet about the order for 300 that just does not show up.  So I escalated the issue to management. I apologize for not doing it sooner. Anyway they say that the order for 300 was lost and they are looking around the warehouse for it. They say that it should have been delivered in December. If they find it, we should get it soon.  I will let you know as soon as I find out anything.
Thanks for you patience.
73, Tom
KM5H

 

(JAN 4, 2008)

Buy 4 is now Closed.
Since then, I have gotten email expressing interest in 12 more which is almost half of a new buy of 25. So I will just keep doing the for a while.
I am thinking that there will be more excellent work like that of Mike KF4BQ and Guido PE1NNZ and others which will generate even more orders. Way to go guys.

73 Tom, KM5H
 

 (JAN 3, 2008)

I just submitted an order for 50 more Si570's even though I have 44 paid.  If history means anything, the other 6 will be gone before the order arrives.
Also they say that 300 are in transit from the factory so I expect to receive those and start shipping them in a week or so.
Keep checking softrockradio.org/Si570 for details.

73, Tom
KM5H
 

(DEC 31st, 2007)

I had to go to two post offices today (first one closed at noon), but all of the LVDS parts that came in this week are in the mail. The 6 week lead time if nearly up so I hope to receive more soon.
The buy 4 is already up to 23 paid so any payments more than two will roll into buy 5.
There have been some requests for the CMOS version and I assume less accuracy and therefore less cost(otherwise CMOS & LVDS cost the same).  I am not against doing a buy of 25 of those if there is enough interest.  Email me directly.
Tom
KM5H

(DEC 30th 2007)

First, I received 50 of the LDVS version and will getting them in the mail tomorrow. It seems like I should have gotten more. I will check on that tomorrow. I ship out in the order that payment was received.

Second, for a group buy 4, I have 5 paid.  All I need is 20 more to order so if you are interested, now is the time.
I will update the status on softrockradio.org later today so you will know to watch your mailbox (an S will be added to the ship column).
Thanks
Tom
KM5H

(DEC 21, 2007)

All 100 of the CMOS versions have been shipped. Waiting for more to arrive.

Thanks, Tom  

KM5H

(DEC 19, 2007)

The FedEx guy showed up with 100 of the CMOS version at 5:30 yesterday afternoon. I just mailed about 25 and have another 25 packaged to be mailed later this afternoon. I plan to have the others ready to mail later today. It took over 6 hours to get those 50 packaged but I am getting better at it. I have several cross checks to make sure I don't make any mistakes. I appreciate Tony more and more. 73, Tom KM5H

(DEC 13, 2007)

Good news! My credit card was charged for 100 of the A option chips which means that they should be on the way to me. I will let you know when they arrive and will quickly get them on the way to you. I have enough paid orders to order 25 more of the B option chips. I will do that tomorrow. You can send money for the next 25 if you want, but I can't guarantee that there will be enough. I will of course refund if there is not enough for another order. Tom KM5H

(DEC 6, 2007)

Somehow I did not communicate very well. If one payment is sent the 30 cents is included. If you have to send two payments because the first one was wrong then add the 30 cents to the second. Sorry.

(DEC 6, 2007)

OK, OK I am opening up the next buy of the Si570. Because the demand has slowed, I have to switch to the 25 price from the 100 price. Those of you who sent money already will have to send more or I will refund if that is what you want. For PayPal you will have to add 30 cents for the additional fee. The new prices are:

PayPal to my email address

(DEC 4, 2007)

I got several comments about how fast the buys have been moving and that some were not able to order in time. I agree with you. In fact, if you think it is moving fast, you should be in my shoes. The other complaint is that it was not clear when the second "open" period began. I agree that while it was stated, it was not totally clear unless my status was read completely. Sorry, I should have made it more clear. The problem is that the minimum order is 50 parts at a time. I have no control over that. When, I warned that the 50 point was getting close, I was flooded with orders and had to shut it off before it went past 50. So, now what do I do? I have eliminated the A option and the only part that I will work with is the LVDS part since it is the most popular. One possibility is that we now move to groups of 25. The price for one goes from $18 to $22 and 2 goes from $33 to $41 and so on. So, those who missed the previous orders, are you still interested? Please email directly to me rather than the whole group.

Tom KM5H

(NOV 26, 2007 a little later)

The second order group buy is now closed. We have reached 50. Send no more money now. If the demand continues, I would be willing to go for another 50. There are still over a hundred people who have expressed interest but have not paid, so we will see.

Tom, KM5H

(NOV 26, 2007)

Since the interest in the A part has only generated 7 payments, no new orders will be accepted for the A part. I know that one person has requested to switch to a B which will leave 5. If anyone else is willing to switch, let me know. For one A to B switch the additional funds will be $2.30 and for two $4.30. Let me know. On the B or LVDS part we are really close to the 50 limit. The demand is pretty slow and very soon, I will have to stop accepting payments for them.\

Thanks, Tom KM5H

(NOV 20, 2007)

I received some disappointing news today. Avnet is now are giving me 6 to 8 week delivery rather than the 4 to 6 weeks (before the order) with a date of Jan 10. I have ask them to expidite this as much as possible even if it means getting a partial order. They have promised an answer by Monday. I know you guys are all ready to get to work. I sure am. Also, on the second buy we have 6 A and 22 B paid. Since we need to get to 50, we have a way to go (but sadly plenty of time). I know that some of you with A's on the first order want to switch to B. Maybe we can work something out with these 6 A's on the second order and increase the B orders.

(NOV 15, 2007)

The order for 100 option A and 300 B has been finalized. I hope to have a ship date soon. My credit card company shut off my card thinking that this large charge must be fraud. It was quickly fixed since it really was me. The spreadsheet that goes with this order will be available below soon. Check it out and make sure your part is right. Those of you who made requests but did not bet around to paying will be in another sheet for the next order. Some payments arrived after this buy was closed. Those will be on this second sheet. I need to get up to 50 paid to do another order. It looks like that won't be a problem. I am thinking about just going with the B option in the future. So, if you are willing to switch to B let me know.

Thanks to all. Tom, KM5H


(NOV 14, 2007)

For now, the group buy is closed. Do not send any more money. If the interest continues, and we get at least 25 more requests, I am willing to do another. Please check and make sure that your status is corrent on the spreadsheet below. Later today, I will move the requests that did not send money to another spreadsheet. Thanks to all. Tom KM5H

(NOV 12, 2007)

Orders for Option A are now

closed.

You can still request them, but don't send any money for Option A. Contact me directly if this is a problem for you. Option B is still strong.

(NOV 11, 2007)

The orders for option A are slowing down. Paid orders are at 91 at the moment. I have decided to stop taking orders for A at 100. If there is still demand, I will consider taking more orders at a little over $2 per part more because the cost will be the Quantity 25 price. Demand for option B is still strong.

(NOV 9, 2007)

I just sent the order for the first 150 570BBC000141DG's I don't quite have enough paid orders for the 570CAC000141DG order. The spreadsheet will be updated in a couple of hours. Good News!! I finally have all of the information. I was not able to get out of sales tax, but because I live out in the boonies it will only be 5.4%. Unfortunately, the lead time is 4 to 6 weeks. I am told that once the order is in they may be able to expedite it some.

 

 

PayPal the appropriate U.S. funds to KM5H at Yahoo.com. foreign addresses add $1 per order Fine Print I will order as soon as I get 100 paid orders. The next order will be when I get 50 more and so on. I just found out that to get the good price, I have to order in multiples of 50 each part number. This means that if I get 201 orders, I have a problem to solve. I am confident that I can work it out. One possibility is for some to upgrade to option B or downgrade to option A. Some have already expressed willingness to do that. If you ordered option A and option B you will probably receive them separately. Tom KM5H

To place an order or make changes send an email to Tom Hoflich the address is above, do not post on this website.
Information on the SI-570 and it's possible uses

The CMOS part is easier to interface to CMOS circuits but it's much noisier (jitter). The LVDS version is way more quiet

but it does not interface to CMOS logic directly, in the SoftRock it can connect to where the crystal connects, the built in transistor brings it up to where it will work with the CMOS logic so nothing extra is needed. Make sure you email Tom with which parts you desire.

What is the SI570? It's a programmable Oscillator with fairly low noise compared to similar chips using the I2C serial bus to control it's frequency. It can be used in place of multiple crystals to allow a SoftRock to cover multiple frequency sections. For example a SoftRock 80M/40M could with this chip be able to receive signals in the range of 3.5MHz to 7.5Mhz and everything in-between. You would not only get full band coverage but also get International Flights, Shortwave and government stations in that range. Another possible use is a poor man's signal generator, this chip is capable of working at very high frequencies, the lowest frequency quality chip can go as high as 215MHz. Two persons have already mentioned that they will be laying out PCB boards to allow the use of the chip. The noise specifications are as follows;

Noise figures for the SI570 chip, specially notice the figures for LVDS outputs;

See the links below for

additional information.

 

 

 

 

June 2008 CMOS Orders

There are two types of chips that have been ordered, type "A" and Type "B", See their description below;

A CMOS output chip with 50ppm accuracy and drift ratings.

B. LVDS output with 20ppm accuracy and drift ratings.

Check with Tom as he is only buying the "A" or CMOS version on this order.

 

 

 

June 2008 LVDS Orders

There are two types of chips that have been ordered, type "A" and Type "B", See their description below;

A CMOS output chip with 50ppm accuracy and drift ratings.

B. LVDS output with 20ppm accuracy and drift ratings.

Check with Tom as he is only buying the "B" or LVDS version on this order.

 

May 2008 CMOS Orders

There are two types of chips that have been ordered, type "A" and Type "B", See their description below;

A CMOS output chip with 50ppm accuracy and drift ratings.

B. LVDS output with 20ppm accuracy and drift ratings.

Check with Tom as he is only buying the "A" or CMOS version on this order.

 

 

 

May 2008 LVDS Orders

There are two types of chips that have been ordered, type "A" and Type "B", See their description below;

A CMOS output chip with 50ppm accuracy and drift ratings.

B. LVDS output with 20ppm accuracy and drift ratings.

Check with Tom as he is only buying the "B" or LVDS version on this order.

 

1. Proposal and sample PicAxe code

 

Jan 5, 2008
A couple of months ago I discovered the newly released Silicon Labs Si570. It seemed like a possible solution to the Softrock receivers being limited to the frequency of commonly available crystals.
I was able to get some samples and am very satisfied with the results.
The Si570 can be ordered with a start-up frequency so that it can be used just like a crystal oscillator with only a 3.3 volt regulator and a bypass and a coupling capacitor. I ordered 54.6 MHz to work on 14.1 MHz and 28.224 MHz to work on 7.056 (for easy comparison to the crystal). I am still thinking what an “ideal” startup frequency would be.
But, more important, the Si570 can be programmed to wide range of different frequencies via I2C bus. I used a PICAXE 18X which is cheap and very easy to program and I had one. If I had to buy one, I would probably get the 28X1 which is only a couple of dollars more and much more capable.
Example using the PICAXE:
main:
              i2cslave $AA,i2cslow,i2cbyte        ‘initialize
               readi2c 137,(b6)
               let b6 = b6 | $10
writei2c 137,(b6)                             ‘freeze DCO
               pause 10
               writei2c 7,($05,$42,$b5,$a2,$02,$85)       ' set new frequency for 14.08
               pause 10
 readi2c 137,(b6)
               let b6 = b6 & $EF
               writei2c 137,(b6)              ‘unfreeze DCO
               writei2c 135,($40)
               Pause 10
The new frequency will stay until frequency data is changed.
I wrote an EXCEL spreadsheet to generate the data to set a new frequency. It can be done by hand with the help of a hex calculator (one is included in Windows). The spreadsheet is better. The part that I ordered can be programmed from 10 MHz through 215 MHz.  As you can see this would work thru 6 meters. One size fits all for Softrock.  
Of course, the programming is open to many possibilities. A simple push button added to the PICAXE could increment up the band by 25 kHz or 40 kHz or whatever each time it is pressed. Any processor can be used.  Or, a visual basic program could generate the frequency word and download it to the PICAXE. One could probably implement I2C on the PC and use RS232 control lines to go to the SI570 directly. The possibilities are endless.
Some may be concerned about the quality of the signal out of the Si570. It seems to be very clean and quite to me. But, I have no way to measure it. I have screen prints of Rocky using the crystal that came with the RXTX and one with the Si570 programmed to show the same frequency as the crystal. 
I wrote to Silicon Labs asking about the specification comparison to the ICS601 which I had studied and got the following response:
“The Si570 has much lower jitter than this device.  The ICS601 specifies period jitter (one-sigma) of 18 ps typ, 25 ps max, measured at 125 MHz.  The Si570 specifies period jitter (one-sigma) of 2 ps rms typ.  The Si570 period jitter specification applies to any output frequency and signal format (CMOS, LVPECL, LVDS, CML).”
This seems very positive. I chose CMOS output. One of the other output options may be better.
PICAXE:
This is the minimum circuit to use the 18X from the PICAXE manual. I ran the 18X at 3.3 volts so that I would not have any level shifting issues to the 3.3 volt Si570. On another version, I used a couple of 2N7000’s, to shift from 5 volt to 3.3. But, I like the simpler solution.  
Out 1(pin7) is the I2C serial data and Out 4(pin 10) is the I2C serial clock. They connect directly to the Si570 pins. Each needs a pull-up.  I used 3.3k in my prototype but value is not critical.
The pins at the left are for programming via RS232. I use a USB to serial adapter. See note below.
The programming editor for the PICAXE can be downloaded free and includes the ability to download the software to the PICAXE.
The SI570:
The package is not very convenient (5x7mm), but I mounted it with the pads up and it is easier to solder than SMD.

Only 5 pins are needed.
3.3 v                     SDA (serial data)
Gnd                       SCL(serial clock)
CLK+  (output)
I used a .01 bypass on pin 6 (3.3 v) and a .1 on the output (CLK+). SDA and SCL go to the corresponding pins of the PICAXE. Very easy! 
Interface to Softrock
So far I have only used this with a RXTXv6.2 20/30. I connected CLK+ in place of X101 on the daughter board.  I can easily change the jumper to compare results with the crystal X100. I can’t see any difference between the Si570 and the crystal.
Future
I sent this to Tony and he suggested that it would be pretty easy to make a board with the SI570 in place of the crystals. I am sure that he will be keeping an eye out to see if this is of interest to anyone.
Pricing for the 570CAC000119DG(28.224 MHZ) or 570CAC000123DG(54.6MHz):
 
1:     21.79
25:    15.02
100:   12.02
A group buy would be less than the cost of making one custom crystal.  This will put a Softrock on any frequency.
 
 
 
Notes
Si570 data sheet
https://www.mysilabs.com/public/documents/tpub_doc/dsheet/Timing/Frequency_Control/en/si570.pdf
PICAXE website to get free software and documentation:
http://www.rev-ed.co.uk/picaxe/
Sparkfun.com has the 18X for $9.95 and the 28X1 is $11.95.
Wulfden.org has 18X with basic parts for $11
Wulfden.org also has a programming adapter P2 for only $3 which contains the common programming parts on a RS232 connector for PICAXE’s. Highly recommended if you have any interest in using a PICAXE for anything.
USB to RS232 adapter that I use:
 http://www.parallax.com/detail.asp?product_id=28030
 
 
 

 

2. Information on the SI570 chip.

Below are two pictures of a test, first the standard SoftRock with a crystal and the second one using a SI570 chip. They are very similar with no appreciable extra spurs on added noise.

SoftRock connected to a dummy load using a crystal.

SoftRock connected to a dummy load using the SI570

12-25-2007

Some good news to day, below is an email from Mike Collins KF4BQ, he received his CMOS version of the SI570 and did some test on it, he reports very close results when compared to a crystal oscillator, that is really good news. The LVDS has even lower jitter so it should get even better results. Below is a copy of his email;

To: softrock40@yahoogroups.com
From: "mikecol2" <mikecol@tampabay.rr.com>
Subject: [softrock40] Si570 CMOS version performance

I was able to get one of my Si570 running at the startup freq
(56.32Mhz) and thought I would do some RX performance measurements
against the N2PK XTAL daughter board (56.2Mhz). Even though the freqs
were different I kept the two signal generators a constant from each
center.

One of the concerns folk had was the phase noise performance of the
CMOS version. I did some 1db Blocking RX measurements at different
signal generator spacings to reveal something about the overall phase
noise differences.

The results of the tests came out excellent for the CMOS Si570; almost
identical measurements against the N2PK XTAL oscillator. Example
measurements:

1dB Blocking (100 Khz spacing), 1.0uV(-107dBm) reference: Blocking
level = -7dBm (123dB Dynamic Range) on both Si570 and XTAL osc.

1dB Blocking (2 Khz spacing), 1.0uV(-107dBm) reference: Blocking level
= -40dBm (90dB Dynamic Range) on both Si670 and XTAL osc.

I will put a summary of my testing on a Softrock20MRXTX v6.2 (with
LT6231 in RX amp) in the files section. Also listed is 3rd order DR
IMD (at various spacings) and Noise floor/Sensitivity testing.

Now, if I can just get some I2C controls to work!!

Have fun, Mike Collins KF4BQ

Later he will use his Spectrum analyzer to compare the results of the crystal clock to the Si570.

Look for the link below for a PDF file with the SI570's specifications

3. SI570 usage information



Work in progress



Here is a link sent to me by Dan Daniels Ke5gn to a web site that has a very low cost homemade USB to I2C interface using a low cost AVR Tiny8 chip ;

http://www.harbaum.org/till/i2c_tiny_usb/index.shtml

It's an open project so the source code is available, if one want a fancier version all one needs is to get a AVR chip with more I/O pins and modify the existing software to do whatever additional functions desired. If you want a 2X16 display, interface to a keyboard, use a keypad, frequency knob, or switches, add the extra code. The code maybe adaptable to use with a AVR Butterfly, and it's free.


Here is a quote from a email from Dave Brainerd on another controller possibility;



Another possibility:
A PIC18F2455 chip is $8 in single qty, falling to under $5 for 25. It has an I2C port and a USB port. I use the PIC18F2550(same but more memory) on my 995x and in the upcoming 9912 board. A USB connector is about a $1. Add a crystal a couple of capacitors, a resistor .

And that's about all you would need. Plus, that chip has plenty of horsepower that could be
programmed to drive an external LCD and read external switches allowing control from either
the computer or stand alone. I will look at the cost tomorrow. A board with parts would
probably be more than $10 but less than $20. The only bad thing about the PIC USB chips is
that the initial bootstrap program must be programmed with a programmer. Only after that
can it be programmed over the USB. Microchip does offer a custom programming service
that is somewhat reasonable in price for quantities more than 25 or 50.

Dave - WB6DHW


Here is a comment by Edson Pereira



The PIC18F2455 is an excellent device and could be used as a good
platform for further developments. After some Googling, I have found a
ready-to-use open source unit, the Bit Wacker, which can be purchased
from SparkFun,

www.sparkfun.com/commerce/product_info.php?products_id=762

The Bit Wacker will present itself as a serial interface for Windows,
Mac OSX, and Linux. This simplifies its use greatly, allowing the
programming of the Si570 using a simple terminal spplication.

73,

-- Edson, pu1jte, n1vtn, jf1afn


Here is a comment by Tom Hoflich on a cheaper version



They also have the same thing in a kit for less and it
has the 18F2550.
I one each of these and they are excellent.
<
http://www.sparkfun.com/commerce/product_info.php?products_id=8265
>

Tom KM5H