4.5

Device addressing

To start communication between the bus master and the slave device, the bus master must initiate a Start

condition. Following this, the bus master sends the device select code, shown in Table 3 (most significant bit first).

Table 3. Device select code

Device type identifier(1)

Chip Enable address(2)

RW

b7

b6

b5

b4

b3

b2

b1

b0

Device select code when addressing the memory array

1

0

1

0

E2

E1

E0

RW

Device select code when accessing the Identification page

1

0

1

1

E2

E1

E0

RW

1. The most significant bit, b7, is sent first.

2. E0, E1 and E2 are compared with the value read on input pins E0, E1 and E2.

When the device select code is received, the device only responds if the chip enable address is the same as the

value on the chip enable (E2, E1, E0) inputs.

The 8th bit is the Read/Write bit (RW). This bit is set to 1 for read and 0 for write operations.

If a match occurs on the device select code, the corresponding device gives an acknowledgement on serial data

(SDA) during the 9th bit time. If the device does not match the device select code, it deselects itself from the bus,

and goes into standby mode.

M24512-W M24512-R M24512-DF

Device addressing

DS6520 - Rev 31

page 9/47