I2C bus and tristate interface for V2pro

[Mancini Stephane]

Hi everybody,
I've just downloaded the i2c controller from opencores.org and I was
wondering how to use it within my system.
Indeed, I've a xilinx V2PRO connected to a video encoder SAA7127 to be
configured thru an i2c interface.
Can I directly connect the I2C interface of the SAA7127 and declare a
tristate I/O pad on the V2Pro, being connected internally to the i2c core
?
Thanks a lot for your help

Stéphane

 

[Nitro]

I did not look at the core but I have played with I2C on the Pro. On the
V2pro I think you need to use the tristate control as data out and tie the
tristate driver in to gnd. This gives you the open collector output mode.
You will need to add the pullup resistors on CLK and DATA if the board/part
you are driving does not have them (about 3K for the 100KHz bus.) There was
an answer on the Xilinx page on using the V2pro I/O in open drain mode. I
used the bidi tristate pin and had the input point return to the logic to
sense the bus levels.

Good luck,
Nitro

On Fri, 09 Apr 2004 12:25:15 +0200, Mancini Stephane wrote:

Hi everybody,
I've just downloaded the i2c controller from opencores.org and I was
wondering how to use it within my system.
Indeed, I've a xilinx V2PRO connected to a video encoder SAA7127 to be
configured thru an i2c interface.
Can I directly connect the I2C interface of the SAA7127 and declare a
tristate I/O pad on the V2Pro, being connected internally to the i2c core
?
Thanks a lot for your help

Stéphane