3. SI570 usage information | SoftRock and other SDR Radios SoftRockRadio.org

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Submitted by k5nwa on Mon, 11/05/2007 - 15:03.

Work in progress

Here is a link sent to me by Dan Daniels Ke5gn to a web site that has a very low cost homemade USB to I2C interface using a low cost AVR Tiny8 chip ;

http://www.harbaum.org/till/i2c_tiny_usb/index.shtml

It's an open project so the source code is available, if one want a fancier version all one needs is to get a AVR chip with more I/O pins and modify the existing software to do whatever additional functions desired. If you want a 2X16 display, interface to a keyboard, use a keypad, frequency knob, or switches, add the extra code. The code maybe adaptable to use with a AVR Butterfly, and it's free.

Here is a quote from a email from Dave Brainerd on another controller possibility;

Another possibility:
A PIC18F2455 chip is $8 in single qty, falling to under $5 for 25. It has an I2C port and a USB port. I use the PIC18F2550(same but more memory) on my 995x and in the upcoming 9912 board. A USB connector is about a $1. Add a crystal a couple of capacitors, a resistor .

And that's about all you would need. Plus, that chip has plenty of horsepower that could be
programmed to drive an external LCD and read external switches allowing control from either
the computer or stand alone. I will look at the cost tomorrow. A board with parts would
probably be more than $10 but less than $20. The only bad thing about the PIC USB chips is
that the initial bootstrap program must be programmed with a programmer. Only after that
can it be programmed over the USB. Microchip does offer a custom programming service
that is somewhat reasonable in price for quantities more than 25 or 50.

Dave - WB6DHW

Here is a comment by Edson Pereira

The PIC18F2455 is an excellent device and could be used as a good
platform for further developments. After some Googling, I have found a
ready-to-use open source unit, the Bit Wacker, which can be purchased
from SparkFun,

www.sparkfun.com/commerce/product_info.php?products_id=762

The Bit Wacker will present itself as a serial interface for Windows,
Mac OSX, and Linux. This simplifies its use greatly, allowing the
programming of the Si570 using a simple terminal spplication.

73,

-- Edson, pu1jte, n1vtn, jf1afn

Here is a comment by Tom Hoflich on a cheaper version

They also have the same thing in a kit for less and it
has the 18F2550.
I one each of these and they are excellent.
<
http://www.sparkfun.com/commerce/product_info.php?products_id=8265
>

Tom KM5H