October 2008 I have added some notes below to guide you to find information on the use of the Si570 and the Softrock SDR. 

The use of the Si570 was proposed as a way of giving the Softrock SDR more frequency agility. The frequency is specified from 10MHz to 210MHz, some are specified to beyond 1GHz. They actually all start at 3.5MHz, the upper frequency is often much higher than specified. Read the information at www.silabs.com/ enter Si570 in the search box. The Si570 is not marketed as a radio device although it's signal purity seems good enough to satisfy many. It certainly is better than many DDS sources! It is reasonably stable and can be set very precisely.

Last opened for editing 11 October 2008 Probably only slight change. I try to remember to put these in italic.

http://groups.yahoo.com/group/softrock40/  This is where it starts, join this group, look through the Files section and pictures, a specific subject may be found by searching the messages. The information is all there but difficult to find. The Si570 has a startup frequency specified at the time of ordering. This is not a real VFO substitute but fast changes can be made via its I2C pins that will satisfy most users. The group has details of control using a printer port (LPT), Serial (COM) port, USB, PIC, PICAXE, two stand-alone controllers . Other methods are being developed. This is still a new device. 

Yahoo (and other) groups. These can be amazing! People from all round the world share their particular expertise. Tom has distributed hundreds (maybe well over a thousand?) of Si570s to members of the group who would not have even heard of it. In the unlikely event of you never having joined such a group, don't be afraid. Nothing is required of you, just join and read what information others have provided.

http://www.softrockradio.org/ is an attempt to sort out the basic information about the Softrock project. A member is arranging group buys of this device for other members of this group.

Getting an Si570

http://www.softrockradio.org/si570  Or try SiLabs for two samples, but be sure of the specifications you require. The default settings are adequate but can give problems with some of the control methods. Two types are relevant to the Softrock. Many favour the slightly cheaper CMOS. The LVDS is higher stability and goes higher in frequency. (Far higher than required for Softrock) At the moment Tony caters for both in his kits. The Softrock local oscillator is four times the receive frequency so the SI570 does allow low frequency reception. Message regarding spurious outputs from the Si570. http://groups.yahoo.com/group/softrock40/message/23882 Apart from harmonics (the output is square wave) spurii are low, LVDS is best.


Getting a Softrock  

You'll find on this page http://www.softrockradio.org/SoftRock  (*how to purchase* link on this page as well) Like all web pages it may not be completely up to date. Tony, KB9YIG, the kit producer, regularly posts the information on the Softrock list. Tony is supplying the CMOS Si570 with his kits, if required.
 http://groups.yahoo.com/group/softrock40/  You may only need to look back a few days, a request on the list usually gets a reply from him. Beginners, this is all you need! The Yahoo group is full of related discussion, but a kit from Tony is all that is needed. (Plus a computer with a stereo soundcard.)

Building a Softrock.

http://golddredgervideo.com/wb5rvz/ The experienced constructor just needs Tony's instructions. This site brings it all together. Don't be put off! I have built 7 Softrocks and never used a dual channel oscilloscope or audio signal generator. An RF signal generator may help but a transceiver running low power into a dummy load can be substituted (no direct connection!) A receiver can be used as a frequency counter, tune to zero beat (as best you can) on SSB to give a rough idea. As an example a short antenna wire placed close to a Softrock will detect the divided centre frequency.

There are various attempts to facilitate fault finding, but a post to the group usually gets a reply, even though the question has been asked many times before! One thing that is sometimes not expected is a "spike" in the centre of the SDR program's waterfall. This is normally obvious unless a very good soundcard is used. What should not be normal is a "mound" each side of this spike. The Softrock is very sensitive to ground loops and should be connected to the computer ground by just one link. Experiment, anything else that is connected to the Softrock may also ground to the computer in a way that is not obvious. For example a PSU may be grounded, in that case try just connecting the positive to the Softrock. An isolated PSU would be best. I usually find that the audio cable ground is the best, anything else connecting the Softrock to the computer has it's ground connection broken. It is best to get this right before putting the board in a case, when you do insulate any sockets put on a metal box so a ground loop is not introduced. Try to avoid making and breaking connections when power is applied. Some have got round the ground loop problem by using transformer coupling but that may cause problems and they need to be chosen with care.

 http://golddredgervideo.com/wb5rvz/RXTX_V6_3/image_rejection_hints.htm Robby has now started some pages about setting up. The image is an equal distance on the opposite side of centre to the wanted frequency. Rocky, and some other software self-adjusts on receive but all need setting up manually for transmitting.

http://ewjt.com/kd5tfd/sdr1k-notebook/sr40/sr6-production/index.html Some examples of Power SDR with a good soundcard. There may be a large spike in the centre when using a card of lower quality. This should be just a spike, a "mound" around this spike could be the effects of a ground loop. At the bottom are some nice oscilloscope pictures, I suspect a very nice oscilloscope was used! This is a v6 Softrock, but they are all basically the same.

For information surrounding the Softrock 
 http://groups.yahoo.com/group/softrock40/files  Tony, KB9YIG has sections for each version. Some will be obsolete as is the picture at the head of the Yahoo Group! Much information is hidden in this file section.

Version 6.2. http://groups.yahoo.com/group/softrock40/files/RXTXv6.2%20files/ 
Version8.3 Lite  http://groups.yahoo.com/group/softrock40/files/Lite%2BXtall%20v8.3/ RX only with Si570

Lite+USB Xtall v8.4 http://groups.yahoo.com/group/softrock40/files/Lite%2BUSB%20Xtall%20v8.4/ 

And now Lite+USB Xtall v9.0 http://groups.yahoo.com/group/softrock40/files/Lite%2BUSB%20Xtall%20v9.0%20docs/ All HF receive, Si570 and USB control on one board.

Xtall Daughter Board  http://groups.yahoo.com/group/softrock40/files/XTALL%20daughter%20board/XTALLv1.1%20documents/  adds the Si570 to older Softrocks

RX/TX v6.3 Si570 all band options http://groups.yahoo.com/group/softrock40/files/RXTX%2BXtall%20v6.3%20files/ 

USB interface http://groups.yahoo.com/group/softrock40/files/USB%20I2C%20Interface%20board/ controls Si570. Adds CW paddle/PTT for Rocky.

For information about setting the frequency of the  Si570, reprogramming the PIC (and PICAXE)

Tom KM5H has developed PICAXE and PIC programs to control the Si570. http://groups.yahoo.com/group/softrock40/files/XTALL%20Software/  Also info on editing the hex file. The most used one has 16 frequencies, there is one that has 40, v2.5, with a slightly different way of selection. These have a self-adjust feature that corrects the settings for individual Si570s. This will probably only work for Si570s with the specification that he supplies. (56.32MHz startup.) 
My message 20798, 21048 Read this edited version. gives my experiences regarding programming the PIC and editing the hex. Winpic800 http://www.winpic800.com/index.php?lang=en  Winpic800 is a program for using a PIC programmer to write your personalised frequencies into a PIC. THIS IS EASY!   Note this program started up in the Catalan? language. Click on "Idioma" and your language may be selected, this makes it a little easier! 

Calculating the Registers for your personalised PIC.  Dick, K9IVB's Excel program http://groups.yahoo.com/group/softrock40/files/K9IVB-Si570/  Xtall-Calc2-VBA.xls will output Tom's v2.4p hex file that will self adjust the PIC to your Si570 giving centre frequencies well within 100Hz of nominal. Most will be much closer.  It outputs three hex files but the v2.4p seems to me to be the best. There is now Xtall-v25-Calc.xls This will produce a 40 frequency v2.5 hex file. The Excel programs all require the Analysis tool pack Add-In. Normally the add-ins must be first installed and then activated on the Tools drop down menu - if the box does not have a checkmark the add-in is not working.  If you really want to produce your own figures but do not have Excel there is a calculator in the SiLabs Evaluation Software https://www.silabs.com/Pages/default.aspx Enter Si570 in "Keyword Search", the data and software will be listed. When installed some of it will not work because you need the Evaluation Board  BUT the calculator software will. Other Excel calculators can be found here http://groups.yahoo.com/group/softrock40/files/KM5H/   Open Office will open the Excel files but would not run Dick's latest. But they do show how the data is arranged if you want to manually edit using Winpic800.  The Si570 can be set very precisely but this requires manual editing of the hex file, not difficult, see links above. I have crudely hacked Dick's Excel files to produce a v2.4.hex and v2.5.hex that do not self-adjust. These output settings very close to the required frequencies when the exact values for a particular Si570 are entered. (These seem to work but have not been approved by Dick)

 http://hammap.smallcpu.org/softrock/  Detailing the hex file modification procedure. This uses Winpic, Winpic800 makes editing the data very much easier for the two finger typist, with less chance of a mistake, see above, but is slightly different.

In message 23234 Tony is offering to supply a personal PIC burnt with a hex file you supply.   >I am willing to provide custom PIC devices in filling kit orders for 
the XTALL v1.1 kit, the Lite+Xtall v8.3 kit or the RXTX+Xtall v6.3 kit. I would ask that a request for a custom PIC be e-mailed to me with an attached HEX file and a note to help me link the custom PIC request to a specific order.

If you do not have Excel just list your 16 required frequencies and it would only take someone a few minutes to produce and send you a customised version of Tom's 2.4p.hex file. (Or the 40 frequency v2.5)  I could do this. I can also program a PIC so if anyone wants this done let me know so we may arrange something. Any frequency for the Softrock may be calculated, not only amateur bands. Alan G4ZFQ That's me! Email address on image at bottom of page.

PARALLEL PORT CONTROL of the SI570.

 PE1NNZ has a parallel port control method. http://groups.yahoo.com/group/softrock40/files/Si570/LPT1/ this is used several ways, incorporated in SDR programs. WB8LGA uses this in a stand-alone computer program.. http://groups.yahoo.com/group/softrock40/files/WB8LGA/ (DDS Si570.zip) sets the Si570 from 3.5MHz to 440MHz. Also see SV1EIA's version of Power SDR, below.

USB CONTROL of the SI570

http://www.sdr-kits.net/  This seems to be an answer if you do not have a parallel port. A USB connected controller. Get an 8.3 without an Si570 and connect this. Now Tony is producing Softrock v8.4 with integrated control.  The web site shows what SDR software will work with this controller. Note the instruction PDF shows a connection to the Softrock that will create an ground loop. The coax outer should normally be left disconnected at the Softrock end. It is suggested that leaving one end of this coax screen disconnected will cause it to radiate, I'm not sure, some experimenting may be required.  See note about Tony's v8.4 below, he uses the line in ground to take the USB return. (Do not connect the USB -ve. DO NOT PLUG or UNPLUG the LINE IN when USB is PLUGGED IN.)

Si570 Type:- It is recommended to use the CMOS with this kit, but if you have the LVDS it may be used with Softrocks.  Look at http://www.sdr-kits.net/hiddentest/index_files/LVDS%2020interfacing.pdf  The LVDS has slightly higher specifications but the difference may not be noticed. The more adventurous could use a receiver like the FIN1002. This option is available in all of Tony's current kits containing the Si570.

USB DRIVER AND SOFTWARE From http://www.mydarc.de/dg8saq/SI570/index.shtml  Here you can download "SOFTWARE AND SCHEMATICS:" SI570_firmware.zip. Extract this to a convenient place. First load drivers. Insert USB plug and direct the "Wizard" to the SI570_firmware folder in the extracted folder. Then the drivers are installed. If you miss this and the driver does not get installed go to "Device Manager", find the "Unknown USB Device" and "Update the Driver", directing it to the folder.
Click "Easy to use PC software" this gives you USB_Synth.zip. Extract the .exe. This enables one to set the frequency independent of an SDR program. (This sets the Si570 to any frequency within its range, try outside their specification, I have at least one of Tom's LVDSs that goes to 700MHz (or higher?)
All this is in the PDF at http://www.sdr-kits.net/  Click "SDR-Synthesizer Kit Documentation (PDF File)" for USB-Synthesizer Kit Instructions v10.PDF and "USB Synthesizer Kit Update 1" for USB Synthesizer Kit Update 1.PDF
For Tom, DG8SAQ's USB troubleshooting http://groups.yahoo.com/group/softrock40/files/DG8SAQ/AVR-SI570-Troubleshooting.pdf  this includes a link to M$ usbview www.mydarc.de/dg8saq/hidden/usbview.zip 
Included in the software is a  USB test program. It will read the Si570 so its frequency could be set, then the registers read to be transferred to a PIC  for specialist use. TOM WARNS, "DO NOT USE ANY OTHER BUTTONS ON SI570_USB_Test UNLESS YOU EXACTLY KNOW WHAT YOU ARE DOING. YOU MIGHT CORRUPT THE AVR EEPROM". See his PDF!

Now Tony is now producing a similar board to interface USB with the Si570 on his kits. http://groups.yahoo.com/group/softrock40/message/24140 This is likely to be the best way to control it, just plugging in where the PIC goes. As in many of these sort of additions the source is available for those who wish to develop further, or customise. This board uses the controller from SDR Kits  above, so the DG8SAQ software above also works with it. NOTE Tony's way of connection on the Softrock v8.4 INTEGRATED USB CONTROL:-  "The electrical connections to the PC from the v8.4 board involve only the soundcard line-in cable and the two data lines in the USB port connection. This results in only a single ground connection between the v8.4 board and the PC, the ground in the line-in cable. With only a single ground connection to the PC the center frequency noise is very low, however, the USB control of the Si570 seems to be good." Since then problems have been noted, I rectified a lack of control by connecting a 100nF between the two grounds, Tony has used some filtering in the v9.0 Lite.

SERIAL. There is now a means of controlling the Si570 using new software in the PIC and connecting to the serial port. A version of Power SDR is used. http://hammap.smallcpu.org/softrock/rs232_509.html This is for more advanced users. It is possible to have 8 switched frequencies as well. http://hammap.smallcpu.org/softrock/rs232_683.html uses the original PIC, but no switched frequencies. The PICs require programming. There is also a small program to set frequency independently. As with many additions, it is possible that this may be developed further.

An earlier, more basic, serial control method using a PICAXE has just been updated. http://groups.yahoo.com/group/softrock40/files/WC5MC/PAXTERM570/ PAXTERM570v072.bas and a PDF. This uses Hyperterm (Found in Accessories - Communication) to send the hex string to the Si570.

Two stand-alone controller kits are available.  

These two kits allow the Si570 to be used with any project without a computer! They may be interfaced with a Softrock that already has a Si570. Build them without the Si570 and interface them like Tony's USB controller, using the PIC socket. They both have a large number of memories for direct frequency input. These will set the Si570 to VHF and higher. 

Si570 VFO controller http://home.austin.rr.com/wa6ufq//universal_vfo_controller.html This comes as a board, PIC and parts list from Digikey. Parts may be sourced elsewhere, the LCD is a standard 2x16 as sold everywhere. Si570 frequency minimum 10MHz so ÷ 8 will be needed for 160m. By setting the Si570 startup frequency to its exact value this controller allows setting to within a few Hz. Also controls DDS30/60. This should have an update when the code for the Kees controller is finalised. They both use code developed by John, K5JHF.

A complete kit from Kees, K5BCQ, http://groups.yahoo.com/group/softrock40/message/23997 This is good. It controls the Si570 from 3.5MHz and works with a 10MHz startup device as well. (Some of us got samples, not realising that software was being written for 56.32MHz startup only.) It has lots of memories and will control band switching. Like the WA6UQF frequency may be set accurately and there are offset and multiplier settings. Switch off and restart after setting the start frequency. The code has been fixed and it now works well. . 12 September, maybe all the little bugs have been found!

 http://wb6dhw.com/  This site and it's Yahoo group now includes the Si570 as well as DDS.

Many other ways are detailed in the Softrock group files, but take some finding!

Some SDR Software

ROCKY PROBABLY THE EASIEST SOFTWARE TO GET GOING. For CW and PSK transmit and SSB receive maybe you will not beat Rocky. http://www.dxatlas.com/Rocky This works with the USB controller.
In message # 21692 Tony explains how to setup Rocky for 40 fixed  frequencies. http://groups.yahoo.com/group/softrock40/message/21692      Or read it here with my notes added.

A MESSAGE FROM TONY TO HELP BEGINNERS WITH ROCKY.

"Please try the Rocky 3.6 software as a start in getting the v6.3 RXTX+Xtall board to play properly. [Or any SDR]
Alex has lots of good information on using Rocky on his website:
Rocky Software http://www.dxatlas.com/rocky/ >
There is a link posted within Alex's information for using a USB connection with the Si570 and getting the USB driver.
The paddle input for use with Rocky is through the USB I2C interface board, connections K1, K2 and ground. Also on the USB I2C interface board is a PTT output that may be connected to the PTT I hole on the RXTX board so that Rocky controls RX/TX switching. The USB I2C board map shows the connections to the board.
I think if you will go carefully through the information Alex has posted on his website you will be able to get the RXTX board playing properly."

POWER SDR IS MORE VERSATILE, SLIGHTLY MORE SETUP OPTIONS, THEREFORE IT IS BETTER TO TRY THIS ONCE THE SOFTROCK IS WORKING. There are different versions customised for different purposes. PowerSDR-SR40 http://powersdr-sr40.sourceforge.net/ couples a Softrock with a Si570 to enable control via a parallel port. (LPT) Look for other versions on the Yahoo group http://groups.yahoo.com/group/softrock40/files/SV1EIA/ now it is being sited here http://code.google.com/p/powersdr-iq/ Downloads There soon may be  a version to control the Si570 by a serial port. A version with USB control via a Brainard board (Not Tony's or SDR Kits) is available. Of course, like all SDR programs, Power SDR may be used with an independent Si570 controller.

 http://www.wu2x.com/sdr.html A version of the PowerSDR software designed for those using the Softrock as an IF panadaptor in a radio with CAT. Use it with HRD. (Ham Radio Deluxe)       Using it with Softrock http://www.zs6buj.com/files/PowerSDR-sr40_Setup.pdf  


KGKSDR http://www.m0kgk.co.uk/sdr/index.php and his Yahoo group. http://groups.yahoo.com/group/kgksdr/  CW, SSB transmit with receive only for AM and FM

Winrad http://www.winrad.org/winrad/ a good RX only program. Alberto is giving up his development and will be releasing the source for others. Final Version is now released. 

G8JCFSDR http://www.g8jcf.dyndns.org/ www.alltomelektronik.se/ Files/070565-QuickStartGuide.pdf 

DRM Dream  http://pdis.rnw.nl/norbert/inst_dream.exe This may be used with a Softrock to receive short wave DRM broadcasts (and analogue modes!). (installation file, default to C:\ and no shortcut is made.) IT HAS COME TO MY ATTENTION THAT THIS PROGRAM REQUIRES A SPECIAL SHORTCUT TO START IN STAND-ALONE I/Q MODE. It appears to work when started normally but is in the mode for PSDR. Cesco says it works better in I/Q mode. I have not yet found up to date information so include this:-

When you install Dream take note of where it installs, C:\Dream by default, you may wish to direct it to "C:\Program Files\Dream\"  Opening the folder and double clicking "Dream.exe" starts it in normal mode, NOT I/Q mode. This will work with a Softrock but not well. The program needs to be started by a Command Line for I/Q use. "Start - Run - Type in "C:\Program Files\Dream\dream" -c 3 OR "C:\Program Files\Dream\dream" -c 4  . (This is if you have put it in "C:\Program Files". Include the "".)  The "3 or 4" cause the sideband to be reversed, try each for best results, it may not work using the wrong setting, You may have to toggle the "flip spectrum" box in the Evaluation Dialog to be able to decode a signal.

A Dream.bat file may be created containing the text.  A .bat file is a text file but renamed with the .bat extension. A shortcut to this file may be made and placed on the Desktop or in the Start Menu. When the program is running View - Station Dialog.. opens a list of DRM stations. Update this and select a suitable frequency. Setting the Si570 centre frequency 10KHz below the signal frequency works, see Jan's remark.  The SNR and waterfall etc may be observed by View - Evaluation Dialog..  http://www.wwdxc.de/drm.htm   can be good site for schedules and TX / reception info. 

Jan says "I have tested the Softrock V8.3 and V9.0 RX with Dream decoder in DRM and CW and SSB (Settings  - AM (analog)) modes and it works very well indeed. You may use "Si570 USB Controller" application by Tom DG8SAQ to set the frequency of the Si570. The setup parameters should be set to: Frequency Multiplier 4 and offset 40000 - then set the IF on DREAM to +10 KHz and the frequency read-out should be accurate." 

A site having links to just about all aspects of SDR http://f4dan.free.fr/sdr_eng.html 

Modes not yet supported by these SDR programs.

This is getting a bit more complicated, but many modes could be run together with an SDR program. The problem is going to be getting audio from one to another. One way is to use a separate soundcard for the other program and link them together by audio cables. I have found that three USB audio "cards" will operate together. Just plug them in, sorting out which is which with the software can be a matter of trial and error.

Recently discussion about Virtual Audio Cable (VAC) has described how to link programs by software, as time goes by maybe programs will have this linking built in. Some soundcard drivers may allow linking by loopback, (What you hear)

Temperature Stability. At 5MHz (divided frequency) the frequency has varied 3Hz over a week when the room has varied 5 degrees Centigrade. I have mounted one on a Khune crystal heater and observed a movement of around 1Hz under similar conditions. The Khune heater holds a temperature of 40 Centigrade so would not work well in the tropics.

HOMEMADE BOARDS a cheap way of making "PCBs". I've lots of double-sided board which I use for my projects. Some Si570 related examples.

September 2008 G4ZFQ

http://homepages.wightcable.net/~g4zfq/ Main Site Index

The background is an Argo display of QRSS reception on 80m.