LE2432DXA

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9

4) Acknowledge Bit (ACK)

The Acknowledge Bit is used to indicate a successful byte data transfer. The receiver sends a zero to

acknowledge that it has received each word (Device Code, Slave Address etc) from the transmitter.

5) Device addressing

To transmit between the bus master and slave device (EEPROM), the master must send a Start condition

to the EEPROM. The device address word of the EEPROM consists of 4-bit Device Code, 3-bit Slave

Device address code and 1-bit read/write code. By sending these, it becomes possible to communicate

between the bus master and the EEPROM.

The upper 4-bit of the device address word are called the Device Code, the Device Code of the EEPROM

uses 1010b fixed code. This device has the 3-bit of the Slave Device address as the Slave address (S0,

S1, S2). The value of S0 and S1 fixed S0=0, S1=0 internally. This device can connect up to two devices

on the bus controlled by S2 value.

When the Device Code is received on the SDA, the device only responds if Slave address pin tied to VCC

or GND is the same as the Slave address signal input. The 8

Read operation and 0 for Write operation. If a match occurs on the Device Code, the corresponding

device gives an acknowledgement on SDA during the 9

Code, it deselects itself from the bus, and goes into the Standby mode. Use the Random Read command

when you execute reading after the slave device was switched.

1

0

1

0

S2

S1

S0

R/W

S2 is selected by TEST-pin, S1=0(Fix), S0=0(Fix)

Device Code

Slave

Address

MSB

LSB

Device address word

Acknowledge

Bit output

Start

condition

1

SCL

(From Transmitter)

SDA

(From Transmitter)

SDA

(EEPROM output)

8

9