Re: Si4734 Hardware and Software Guides


Roy <roy.dyball@...>
 

Thank you for the complement Phil.

In the early days of getting my interface working I looked at using RS232 to keep the cost down. An early interface I constructed used the URAT output lines of an FTDI chip by bit banging the normal RS232 lines in an I2C two wire configuration (SDIO SCLK), the trouble was it was too slow and I could not get status information back quick enough by polling. The other problem was I had to convert my interface to the 3 wire legacy control interface from I2C because that is what Tecsun uses in our little radios and I wanted the ability to remove the radio from the computer and be able to go on using it with the changes just made (soft mute off different filter).

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.

Scott has a superior interface to mine in that he is using a Si Labs C8051F321 MCU this allows him to tristate the control lines making a switch not necessary to unhook the radios controller. Also by using an MCU it takes a huge load of the computer because the I/O to the Si4734 is done locally by the MCU. Another good feature is it can store command sequences that can be run without a computer say at power up or at the press of a button.

Cheers Roy.    

  

--- In ultralightdx@..., "just_rtfm" wrote:
>
>
>
> howdy Roy!
>
> thank you. i need to add that info. my original plan was RS232 control. i recently saw your USB/G8 work... excellent job!
>
> regards,
> phil :)
>

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