Re: Si4734 Hardware and Software Guides
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Roy <roy.dyball@...>
Hi Scott Thank you for the link to the sample C code and the explanation. All my code is written in VB.NET 2008. I have many years experience with it from my previous business dealings before I retired and the program was going before I thought too much about it. I have got the 3 wire interface running really well and the 9 bit data word was a real challenge especially in VB.NET, I think the hardest part was getting the half clock cycle delay correct during the bus turn around. Because the Tecsun uses the 3 wire interface I feel it is best to stick with it while they use it because I can unhook my interface, and as soon as I switch the local MCU control lines back in it takes over without a fuss and you can still use any changes you have made until power down while using the radio normally. I am really leaning toward using an MCU like you are doing and am looking forward to seeing your final results. I noticed you have posted more pictures and your radio with interface looks good now it is back together. Cheers Roy.
--- In ultralightdx@..., "sdwillingham" wrote:
> > > > > Roy, > > The 9-bit control word is a bit of a pain, but although it is not > obvious, it is not too hard to use a standard 8-bit SPI-type > interface to communicate with the Si4734. The technique is used > in this software: > > http://www.silabs.com/Support%20Documents/Software/AN264SW.zip > > (See the CONTROL_WRITE and CONTROL_READ macros in file > F320_Si470x_Interface.h. Note, this code is for the Si470x parts, > but works the same for Si473x if you change the chip-address to > 0xA0 instead of 0x60.) > > The basic idea is to do a 2-byte read or write by packaging the > 25-bit command+response or command+data in four 8-bit transactions. > (While manually banging the SENB signal before and after the > 32-bits.) The first 25 bits are as documented for the part. The > last 7 bits just hang on as partial extra response or data. When > SENB is driven high, the last partial transaction is aborted and > the control interface state-machine is reset for a new transaction. > > Perhaps you can simplify your interface with this technique. > > Cheers, > Scott > > --- In ultralightdx@..., "Roy" roy.dyball@ wrote: > > The 3 wire (SDIO SCLK SEN) control interface opened up a big can of > > worms because it uses a non standard nine bit control word. I then > > discovered I could use the advanced bit banging functions of the FTDI > > chip to construct a non standard nine bit word and get my I/O routines > > running fast enough to produce good results. By this time it was clear > > to me that RS-232 would not do the job. > |
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