David,
I've seen no information that the gpio pins are 5v tolerant in any way.
This is however where the DS2483 comes into it's own over the DS2482. It is
possible to power the 1-wire side from 5v, and the i2c from 3.3v in effect it
has an inbuilt level convertor
See: http://datasheets.maxim-ic.com/en/ds/DS2483.pdf Page 5 lists the pin
connections, take particular note of pin3, this is the i2c power supply.
I've used 5v for pin6, vcc, and 3.3v for pin 1, splz
Stuart
On 9 Jun 2012, at 23:58, David Richards -Gmail- wrote:
> My DS2483 sample arrived today so I had to make my Raspi boot the new
> kernel to support it. The problem was with the supporting boot files
> which needed to be updated, I got them from here:
> https://github.com/raspberrypi/firmware, I used the new 3.2.18-rpi+
> kernel with i2c support form here: http://www.bootc.net/
>
> It is working now, but I'm not sure whether the chip should be connected
> to the 3v3 or 5V supply, I think it is safe to connect it to 5V, but I
> have connected it to 3v3. I am not using an i2c level converter, do I
> need to if I power the chip from 5V?
>
> Anyway the 1wire parasitic device I have connected to it is visible but
> not reliably readable. to make it readable I had to issue the
> --ActivePullUp switch on the owserver command line.
>
> The 1wire bust will be getting only 3v3 which will explain the
> unreliable result, this is why I wonder if it is safe to put 5v onto the
> chip without a level converter.
>
> David.
>
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