This page starts with a copy 0f this message https://groups.io/g/softrock40/message/20528?p=,,,20,0,0,0::Created,,12f693,20,2,0,5632744 Only click "See other 7 Messages" if you have a sense of humour:-)
https://sites.google.com/site/g4zfqradio/configuring-a-softrock-sdr/srlitemod
The paragraph below describes the Softrock Lite on the page above.
When Tony announced he was ending his run of the Softrock 6.2 Lites I promptly ordered a couple not realising the version 8 was imminent. I have built one omitting the crystal oscillator and antenna input components. In the empty space left I fitted a 3V3 regulator, Si570 and a FIN1002, the output going to the x4 end of JP1. (So I can /8 to go low frequency.) I put a header in to plug in various BPFs. I replaced the regulator with a 1 amp 7805 with a small heatsink to be able to feed the Si570 regulator. The I2C pins of the Si570 I took to a plug along with 3V3 and ground so different controllers could be plugged in.
The text below, written in the early days of Softrocks refers to earlier methods of controlling the Si570. This needs to be read in conjunction with files here https://groups.io/g/softrock40/files You will have to join the group. If you have a specific need I might find what you need.
I mounted a socket for a 12F693 PIC and switch on a piece of Veroboard along with the necessary resistors to plug in to this.
I used DL4YHF's Winpic and a homebrew JDM PIC programmer (They can be bought) to program the PIC with Tom's hex file, this is the only file you need. (BUT to run Winpic you do need a .dev file from Microchip's MPLAB for the PIC. MPLAB is a free download.) (File - Load and Program Device (CODE+.........) Plugging the PIC in to the Si570 control board confirmed that I had successfully programmed my first PIC. Replacing the PIC in the programmer and reading it showed that the start-up registers had been entered into the PIC's memory. Data 002100. I now use Winpic800, it is self contained and makes manual editing of the data easier.
These readings may then be entered into Mike's Si570 Excel program and the required settings may be calculated to bring the centre frequencies closer to nominal or to calculate other frequencies according to requirements. I wanted to program some frequencies outside the amateur bands, Mike's lookup table does not give HS/N values outside these bands so I used Si Labs Si57x Programmer. This is part of the Si Labs Evaluation software, it has an offline "demo" mode to calculate the registers. This requires the internal crystal frequency to be entered. If you do not have Excel to read this from Mike's program then it may be calculated by measuring the frequency from the Si570. Find the actual crystal frequency by calculating the difference between the expected and actual frequencies and adjusting the nominal 114.285MHz by the same proportion. THESE NOTES REFER TO V2.1.HEX I NOW RECCOMEND YOU USE V2.4p AND WINPIC800. THE DATA IS STORED DIFFERENTLY IN V2.4p.HEX
Winpic enables one to edit the data, this is shown under a separate tab. Carefully edit this. (Edit - Enable HEX editor) Do not edit the first one, 002100, this is the Si570 startup register and will be replaced when the PIC is first used. You will see something like 002108 A3 CC 57 7E 0C 42 FF FF ....... The first six hex figures are those requiring to be replaced with your new calculated values. When finished (Edit - Apply Edits) This can be saved if required (Dump buffer to hex file) Then load this edited data (Device - Program (CODE+DATA+CONFIG))
I am intending to build my last Lite 6.2 with synchronous clocking of one 7474 as in Tony's prototype. [ I did do this, leaving the first one in position gives the option of divide by 8, so the Softrock COULD go down to 440KHz Rx with suitable coils.] Most will find the accuracy of the frequencies programmed into the PIC quite adequate. I detailed in a recent post how I personalised mine. After doing this I realised the frequencies obtained were very slightly out from those I had programmed in. I am talking about splitting hairs here, for example 14Hz low at 3MHz. I measured the Si570 startup frequency, it was 235Hz low. I entered the exact measured startup frequency into Mike's programme, the green area where 56.32MHz appears. It then recalculated the Calc Fxtal to compensate. Recalculating the frequencies and loading the PIC registers with the new figures resulted in outputs very much closer to those required. This may also be done with the Si Labs Programmer. I did not measure the startup frequency when the Si570 was new, I do not know how accurately it was set, it had been on for a month or more so may have aged. I used a GPS source to check my frequency counter, a standard frequency transmission could be used if the PIC is first programmed for one of these frequencies then it can be compared and the difference noted. It will be interesting to see how long the Si570 stays as close as it is. Another I am using has not moved much is a couple of months. A COMMENT FROM TOM ""Each version gets a little better as I learn more about using C. In 2.4 and before, I stored the Si570 registers at location 0. I used Tony's suggestion to repeat the highest frequency in each bank to prevent out of band operation. This is not a big deal on a receiver, but hopefully this will be used on the RXTX and it will be important. I compare the registers read with the register value used to calculate the eeprom values. I then replace the eeprom values with the adjusted value and set a flag so that this done only the first time. So to start over, you have to reprogram the chip. If you edit the data in the eeprom, this adjustment will not happen again unless you reset the flag. You can use the value in the eeprom to calculate your unique frequencies."" TO PRODUCE THE HEX FILES AUTOMATICALLY. Look for the link to Dick's XLS files. I find they will open in "Open Office". I did not get them to run but it does show how the frequency data is organised. Dick says it will run in Office 97 onwards but I have only got it to work in Office 2007. To make one of Tom's self-adjusting .hex files do not alter the default startup values. Only alter these if you wish to edit manually a hex file that has been run. You may use this for precise adjustment as described above but to enter your measured startup frequency you will need to format K10 for 6 places and widen this column a bit. I have fiddled around and modified Dick's xls to output a "run" version of Tom's hex, it seems to work but is not "official". NOTE TONY IS NOW OFFERING TO "BURN" A PIC WHEN ORDERED WITH A SOFTROCK. JUST ASK SOMEONE TO PRODUCE A HEX FILE INCORPORATING YOUR REQUIRED CENTRE FREQUENCIES. THEN SEND IT TO TONY.