how to interface between 3.6V and 5V for I2C communication?

Started by September 15, 2003
Now I try to interface Processor and Audio control IC
but I found Processor has 5V vdd and Audio IC has 3.6V Vdd.
I would like to know how to interface 3.6V and 5V based ICs with I2C communication.
regards
---------------------------------
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There was a thread on the subject of interfacing 3.3V IIC parts to HCS12 at
5V last May on this email list.

The suggestion that I liked the most came from Bob ():

> Download the I2C specification at
>
http://www-eu2.semiconductors.philips.com/acrobat/literature/9398/39340011.pdf
>
> Page 43 shows a simple bidirectional level translation circuit.

The above solution has a trade-off between the power consumption while in
the logic low level, and the maximum speed. This trade-off is determined by
the values of the pull-up resistors.

Your problem may also be easily resolved if you can choose an HCS12 that
can run at 3.3V - like the MC9S12E128 that includes a IIC port.

P.S.
Is there a way for you to change the name line on your postings to this
email list? It currently comes to us as "=?euc-kr?q? ?=".

Doron
Nohau Corporation
HC12 In-Circuit Emulators
www.nohau.com/emul12pc.html

At 02:19 PM 9/15/2003 +0900, you wrote:
>Now I try to interface Processor and Audio control IC
>but I found Processor has 5V vdd and Audio IC has 3.6V Vdd.
>I would like to know how to interface 3.6V and 5V based ICs with I2C
>communication.
>regards


Hi,

As most experts have pointerd out, if the device has a open drain I2C and 5V
tollerant interface you should be able to pull the I2C to 5V. TI provides
nice single (little logic) buffers with open drain outputs to drive low
voltage inputs from a 5V environment.
----- Original Message -----
From: "Doron Fael" <>
To: <>
Sent: Monday, September 15, 2003 1:20 AM
Subject: Re: [68HC12] how to interface between 3.6V and 5V for I2C
communication? >
> There was a thread on the subject of interfacing 3.3V IIC parts to HCS12
at
> 5V last May on this email list.
>
> The suggestion that I liked the most came from Bob ():
>
> > Download the I2C specification at
> >
>
http://www-eu2.semiconductors.philips.com/acrobat/literature/9398/39340011.p
df
> >
> > Page 43 shows a simple bidirectional level translation circuit.
>
> The above solution has a trade-off between the power consumption while in
> the logic low level, and the maximum speed. This trade-off is determined
by
> the values of the pull-up resistors.
>
> Your problem may also be easily resolved if you can choose an HCS12 that
> can run at 3.3V - like the MC9S12E128 that includes a IIC port.
>
> P.S.
> Is there a way for you to change the name line on your postings to this
> email list? It currently comes to us as
"=?euc-kr?q? ?=".
>
> Doron
> Nohau Corporation
> HC12 In-Circuit Emulators
> www.nohau.com/emul12pc.html
>
> At 02:19 PM 9/15/2003 +0900, you wrote:
> >Now I try to interface Processor and Audio control IC
> >but I found Processor has 5V vdd and Audio IC has 3.6V Vdd.
> >I would like to know how to interface 3.6V and 5V based ICs with I2C
> >communication.
> >regards >
>
> -------------------- >
> ">http://docs.yahoo.com/info/terms/