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SMBus library?

Started by Alan Matheson August 27, 2008
I use I2C bus devices in an instrument, the I2C library supplied with
Dynamic C works very well.

Now I want to use a chip that has an SMBus interface. Superficially this
looks very similar to I2C.

Is it possible to use the I2C library to control these devices. If not is
there a library available anywhere that caters for this bus?

Alan Matheson
--- In r..., "Alan Matheson"
wrote:
>
> I use I2C bus devices in an instrument, the I2C library supplied with
> Dynamic C works very well.
>
> Now I want to use a chip that has an SMBus interface. Superficially this
> looks very similar to I2C.
>
> Is it possible to use the I2C library to control these devices. If
not is
> there a library available anywhere that caters for this bus?
>
> Alan Matheson
>

Hi Alan,

Yes they are pretty much compatible, the main differences are
electrical rather than the protocol. I have used the DC and Softools
(derived from DC) i2c code to access SMBUS chips with no problems. See
this link
http://www.maxim-ic.com/appnotes.cfm/appnote_number/476
for a comparison of the protocols.

Which chip are you trying to access?

Cheers

Martin Honeywill
Thanks for that Martin. I'm looking at the Melexis MLX90614DAA which is a non contact infrared temperature measuring device. Am trying to measure and control the temperature of a liquid seperated from the sensor by two layers of plastic and two air gaps. Not easy.

Regards
Alan Matheson

----- Original Message -----
From: Martin Honeywill
To: r...
Sent: Thursday, August 28, 2008 8:02 PM
Subject: [rabbit-semi] Re: SMBus library?
--- In r..., "Alan Matheson"
wrote:
>
> I use I2C bus devices in an instrument, the I2C library supplied with
> Dynamic C works very well.
>
> Now I want to use a chip that has an SMBus interface. Superficially this
> looks very similar to I2C.
>
> Is it possible to use the I2C library to control these devices. If
not is
> there a library available anywhere that caters for this bus?
>
> Alan Matheson
>

Hi Alan,

Yes they are pretty much compatible, the main differences are
electrical rather than the protocol. I have used the DC and Softools
(derived from DC) i2c code to access SMBUS chips with no problems. See
this link
http://www.maxim-ic.com/appnotes.cfm/appnote_number/476
for a comparison of the protocols.

Which chip are you trying to access?

Cheers

Martin Honeywill
You may need to install an optical conductor in the air gaps in order for
the IR temp sensor to function properly.

That is what I had to do on a CLO2 system.

I installed a optical rod horizontally in the gap between the two plastic
tubes, so the sensor would not reflect off of the first air gap surface.

Good luck.

From: r... [mailto:r...] On
Behalf Of Alan Matheson
Sent: Thursday, August 28, 2008 4:45 PM
To: r...
Subject: [SPAM] Re: [rabbit-semi] Re: SMBus library?

Thanks for that Martin. I'm looking at the Melexis MLX90614DAA which is a
non contact infrared temperature measuring device. Am trying to measure and
control the temperature of a liquid seperated from the sensor by two layers
of plastic and two air gaps. Not easy.

Regards

Alan Matheson

----- Original Message -----

From: Martin Honeywill

To: r...

Sent: Thursday, August 28, 2008 8:02 PM

Subject: [rabbit-semi] Re: SMBus library?

--- In r..., "Alan Matheson"
wrote:
>
> I use I2C bus devices in an instrument, the I2C library supplied with
> Dynamic C works very well.
>
> Now I want to use a chip that has an SMBus interface. Superficially this
> looks very similar to I2C.
>
> Is it possible to use the I2C library to control these devices. If
not is
> there a library available anywhere that caters for this bus?
>
> Alan Matheson
>

Hi Alan,

Yes they are pretty much compatible, the main differences are
electrical rather than the protocol. I have used the DC and Softools
(derived from DC) i2c code to access SMBUS chips with no problems. See
this link
http://www.maxim-ic.com/appnotes.cfm/appnote_number/476
for a comparison of the protocols.

Which chip are you trying to access?

Cheers

Martin Honeywill