Hi !

(and sorry for the the "long blah blah", I'm working on that...)

Jamie Jensen wrote :

> I've been reading thru the app notes on Mchip website, and
> found some sample code for I2C, but it I don't think its
> quite what I am looking for.  I have a F877 that I need to
> run in master mode only, tied to a phillips 9554

Now, what you *are* talking about is the PCA9554, right ?
If it's not, hit delete here...

> where half
> the I/O is input, the other half of course is output.
> In doing the research,

Using the actual data sheet for this device ?

> if you setup the MSSP for I2C (rather
> than spi) and to talk to the 9554, you always need to send
> out the address,

Yes

> then the command.

It depends...

> Does the 9554 always
> expect that in that order?  In other words, if I want to only
> read from the device, do I always have to send out
> address

yes

> ,command

no

> , and then I can read?

Why ask about something that is perfectly clear from the
data sheet ? It's only 15 pages long and the answer to
your question is expressed in just 2-3 sentences and using two
figures to make it clearer.

But why not check for yourself at :

http://www.semiconductors.philips.com/acrobat/datasheets/PCA9554_9554A_5.pdf


> If someone has some sample code in asm that they have used in
> the past for a similar device that would help

No, sorry...

And note, I have never *used* this device, this is based from a
45 second browse of the data sheet, so I might be wrong :-)
But this device looks as a fairly easy part from a I2C standpoint,
after looking in the data sheet.

Jan-Erik.


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