[hpsdr] CASMIR design v0.4 plus introducing COPERNICUS!

[Lyle Johnson]

Hello Alex!

> Personally it seems like a waste to use an ATLAS slot for
> COPERNICUS, maybe an external card. There's lots of room 
> in my ATX case to mount it!  : )  (hint, hint, hint)

Copernicus will need some sort of control logic to run it.  You could 
reserve space at one edge for the ATLAS DIN connector and put another 
connector in the same area. User than gets a choice of making it 
Atlas-compatible or not.

It would also need space for the DS2431 1-wire ID chip.  If the control 
is via SPI or I2C, then the lines are already predefined for the ATLAS 
bus, making things pretty simple.

I suggest SPI, and use TI TPIC6C595, Allegro A6810 or similar ICs to 
handle the control.  These can sink plenty of current for relay coils.

Alternately, I2C and use PC8574 (or similar) parts with some means to 
strap the address.  Not sure if these can directly drive relays.

Almost as cheap, you could use a small PIC which can be set up as SPI 
slave or I2C slave.  If you run the PIC from 6V, you may be able to 
directly handle 5V coil relays.  Elecraft, for example,  has done this 
for years in the various products.

Finally, please consider the use of latching relays.  They're not 
expensive, the board then remembers its last state, and operating 
current is nil.

73,

Lyle KK7P


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