I want to use an 24LC256 EEPROM. I take a look to the data sheet, on internet and in this forum about how to wire it, and i observed differences about f you resistances in SDA and SCL connections of the EEPROM to Arduino board.
Here is an example where they do not use resistances:
Here is an example where they say that is necessary in both i2C connections:
And the datasheet only say something about resistances in SDA (but do not say anything about resistances in SCL):
So, my questions are:
Is it really necessary resistances on i2c with this eeprom? In both connections (or only on SDA)? What resistance value should i use?
May be they are easy questions, but i don´t want to burn my arduino duemilanove...
Thanks for your help!
AFAIK you always need pullup resistors with I2C, it's an open collector/drain bus, it's possible the first example used the internal ones.
As for the value for a single device and short line it probably doesn't matter much, try 4k7.
Great. Thanks Graynomad!
I will try it.
by the way, i just saw this other example using 4K7 resistances in both SDA and SCL, more over a 0.1uF ceramic capacitor between +5V and GND of the EEPROM. I suposse that to stablilize the power.
more over a 0.1uF ceramic capacitor between +5V and GND of the EEPROM. I suposse that to stablilize the power.
Thanks Coding Badly!!
It works perfectly with 4K7 pull up resistances on SDA and SCL I2C pins.