Re: [Discuss-gnuradio] FrontEnd4702 take 2

[Matt Ettus]

Quoting John Gilmore <address@hidden>:

> > >     There are now two 4702 tuners on the board. The first one has its MA0
> > > pin grounded so it should respond to I2C address 0xC0 and the second has
> its
> > > MA0 pin left open so it should respond to I2C address 0xC2.
> >
> > While we're at it, let's really go all out -- the 4702 can handle 4
> different
> > addresses.  Thus, we could put 2 of these boards, with 2 4702s each, on the
> > USRP at once, necessitating the 4 addresses.  With a pair of 2-pin jumpers
> we
> > can accomodate that.  If you give the address select pin on one 4702 a 15K
> R to
>
> I thought these daughterboards are physically addressable.  If that
> doesn't work for I2C, are there pins left in the interface connector
> that can be wired on the motherboard to +5 or GND to encode the slot
> number?  Wiring these pins to the 4702 address pins (and any other
> chip-selects on the board) would automatically give different
> addresses to as many boards as you plug in.

Each daughterboard has 2 pins set by the motherboard for A0 and A1 for I2C
devices to get their address.  The 4702 doesn't follow that convention, hence
my advice above.

> Doing something like this, to allow many copies of a board to be
> plugged in at once without trouble, is a good idea for any board.  It
> makes the system simple for software, simple for users, and simple for
> hardware builders.

see above.  We've taken care of this.

Matt