Re: Si4734 Hardware and Software Guides


sdwillingham
 

Roy,

A clarification: the code in the reference design I linked to
is actually operating the chip in 3-wire mode. It nicely makes
use of the MCU's SPI interface hardware, but the incoming and
outgoing serial data lines are actually connected together with
a 1 kohm resistor (see the schematic in the app note).

I actually used a version of that code example in the first
version of my interface. That said, I'm back to bit-banging
with my current software.

Yesterday, one of these arrived at my house from Mouser:

http://www.silabs.com/Support%20Documents/TechnicalDocs/ToolStick_F321_DC_UG.pdf

It's quite a lot bigger than my present prototype, but should be
easier to work with in terms of solder points, etc. Last night
I determined that if I cut off the bottom third of the board
(where the potentiometer and switch are), I will be able to fit
the remainder inside my PL-380. (These Tecsuns are remarkable
in their packaging design -- very little wasted space and yet
very easy to dis- and re-assemble.) The PL-380's built-in USB
connector will make this a very stealth modification!

-Scott-

--- In ultralightdx@..., "Roy" <roy.dyball@...> wrote:

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.

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