24512 Ver la hoja de datos (PDF) - STMicroelectronics

Número de pieza

componentes Descripción

Fabricante

24512

512-Kbit serial I²C bus EEPROM

STMicroelectronics 

Device operation

M24512-R, M24512-W, M24512-DR

3.5

Addressing the memory array

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 2 (on Serial Data (SDA), most significant bit first).

The device select code consists of a 4-bit device type identifier, and a 3-bit Chip Enable

“Address” (E2, E1, E0). To address the memory array, the 4-bit Device Type Identifier is

1010b.

Up to eight memory devices can be connected on a single I2C bus. Each one is given a

unique 3-bit code on the Chip Enable (E0, E1, E2) inputs. 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 (E0, E1, E2) 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

acknowledgment 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.

Table 6. Operating modes

Mode

RW bit WC(1)

Current Address

Read

1

X

Random Address

0

X

Read

1

X

Sequential Read

1

X

Byte Write

Page Write

1. X = VIH or VIL.

0

VIL

0

VIL

Bytes

1

1

≥1

1

≤ 128

Initial sequence

Start, device select, RW = 1

Start, device select, RW = 0, Address

re-Start, device select, RW = 1

Similar to Current or Random Address

Read

Start, device select, RW = 0

Start, device select, RW = 0

3.6

Addressing the Identification page (M24512-DR only)

The M24512-DR features an additional memory page, referred to as Identification page.

Read and write operations can be performed on this page, except if a Lock instruction has

been issued to permanently write protect it.

The M24512-DR Identification page is addressed in the same way as the memory array,

except that the 4-bit device type identifier of the device select code is 1011b (see Table 3).

14/39

Doc ID 16459 Rev 19

Share Link: