W dniu 18.11.2012 o 18:16 Sven Geggus <[email protected]> pisze:
> Hello, > > i just got two DS2483 samples (because SOT23 seem to be the most > amateur friendly package of the I2C bus-masters). > I want to connect this device to my Raspberry Pi now. Fist remember that Raspis i2c runs at 3.3V and won't tolarate higher volatges. For testing you can power DS2483 with 3.3V. However the official release does not yet support DS2483. It should be added to the next one. > > Looking at the schematic in the datasheet I have two questions: > > * I need two pullup resistors to 3.3V, while the chip has to be > powered by 5V, right? What size should the resistors have? Raspi has some pull-up resistors so for testing on a breadboard you don't need any but if you are planning a board it should be 4.7 kOhms or less I think. I read it here http://dsscircuits.com/articles/effects-of-varying-i2c-pull-up-resistors.html They can be as small as 0.125 W > * Raspberry Pi does not have a SLPZ connector so in order to enable > the DS2483 would I need to connect this pin to VCC or Ground? AFIK the SLPZ is the pin which selects the voltage of i2c port. DS2483 can operate 1-wire at 5V and i2c at 3.3v simultaneously so you have to connect SLPZ to Raspberrys 3.3 V. From page 5 of DS2483 datasheet Power Supply for I2C Port and Active-Low Control Input to Activate the Low-Power Sleep Mode. This pin can be driven directly by a push-pull port or by an open-drain port with a 2.2kI pullup resistor to the I2C voltage (VCI2C) over the entire operating voltage range. -- p4trykx ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
