I'm a little confused by the instructions in the datasheet for the AT24C512B so looking to get clarification. On the DIP package pins A0, A1 & A2 define the lowest 3 bits of the I2C address. From examples I've seen on youtube for this, the pins are put directly to 5v or GND (exactly as it says in the initial explanation in the relevant section from the Atmel datasheet below:
DEVICE/PAGE ADDRESSES (A2, A1, A0): The A2, A1, and A0 pins are device address inputs
that are hardwired (directly to GND or to Vcc) for compatibility with other AT24Cxx devices.
When the pins are hardwired, as many as eight 512K devices may be addressed on a single bus
system. (Device addressing is discussed in detail under “Device Addressing,” page 8.) A device
is selected when a corresponding hardware and software match is true. If these pins are left
floating, the A2, A1, and A0 pins will be internally pulled down to GND. However, due to capacitive
coupling that may appear during customer applications, Atmel® recommends always
connecting the address pins to a known state. When using a pull-up resistor, Atmel recommends
using 10kΩ or less.
So the way I interpret that is I don't need to put a resistor between the pin and GND to define a 0, as they take care of that inside the chip. I don't understand the last sentence however - under what circumstances would I need the resistor?
Thanks for your advice,