Hardware considerations

AN3171

6/14

Doc ID 17229 Rev 1

1.2

Two ways of accessing the M24LR64-R: RF and I²C

Compared to the M24C64, the M24LR64-R has an additional capability: RF access, made

possible by connecting the AC0 & AC1 pins to a tuned antenna. This modifies the block

diagram of the M24LR64-R. Figure 3 shows the new block diagram.

Figure 3.

M24LR64-R block diagram

One difference between the M24LR64-R and the M24C64 is that the M24C64 can be

accessed only through the I²C bus, whereas the M24LR64-R can be accessed through

either the I²C bus or the RF interface.

Due to the M24LR64-R’s dual access capability, a number of things have to be taken into

account when accessing the device. If an RF request is made while an I²C communication is

ongoing, it will not be served. Likewise, if an I²C request is made during an RF

communication, it will not be served. This has to be taken into account in the system. A

dedicated application note, AN3057, explains “how to manage simultaneously I²C and RF

data transfers with the M24LR64-R”.