Hi,

Hmm, ideally you wouldn't have to resort to tricks like that but if it
works, I see nothing wrong with it. You still want it so that the slave
devices are able to pull SCL low if they're busy processing some data. Of
course, using a 4051 will still allow this.

Ah, but what about the fact that if an 'unselected' slave sees a moving SDA
but a constant (high) SCL, it will in effect see a string of Start / Stop
instructions. Could this be a problem? Could it confuse the slave device?
Maybe a 4052 would solve this, i.e. four differential channels?

Are there no means to select / deselect individual slave devices via a slave
select (SS) pin?

I must admit I'm no I2C expert but trying to learn. I'm just finishing off
my first I2C job - a 400KHz I2C monitor. Bit of a nightmare with an 8MHz AVR
:o)

Kind regards

Trevor

> -----Original Message-----
> From: David Duffy [SMTP:piclist@AUDIOVISUALDEVICES.COM.AU]
> Sent: 22 March 2002 05:58
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      [PIC]: Multiple I2C slaves
>
> Hi All,
> I have an application that needs to talk to multiple I2C devices
> but the chips concerned only have one (fixed) slave address.
> Seeing I was planning to use the hardware I2C port (16F876),
> how does using a mux such as a CD4051 on the clock line
> sound? Pullups would be used on the clock line of each slave.
> Sound feasible?
> Regards...
>
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