EVAL-ADM1026EB datasheet(15/56 Pages) AD

15 / 56 page

ADM1026

Rev. A | Page 15 of 56

Because the EEPROM consists of 128 pages of 64 bytes, the

EEPROM page address consists of the EEPROM address high

byte (from 80h to 9Fh) and the two MSBs of the low byte. The

lower six bits of the EEPROM address (low byte only) specify

addresses within a page and are ignored during an erase

operation.

SLAVE

ADDRESS

EEPROM

ADDRESS

HIGH BYTE

(80h TO 9Fh)

ARBITRARY

DATA

EEPROM

ADDRESS

LOW BYTE

(00h TO FFh)

9 10

Figure 22. EEPROM Page Erasure

Page erasure takes approximately 20 ms. If the EEPROM is

accessed before erasure is complete, the ADM1026 responds

with No Acknowledge.

Last, this protocol is used to write a single byte of data to

EEPROM. In this case, the command byte is the high byte of the

EEPROM address from 80h to 9Fh. The first data byte is the low

byte of the EEPROM address, and the second data byte is the

actual data. Bit 1 of EEPROM Register 3 must be set. This is

illustrated in Figure 23.

SLAVE

ADDRESS

EEPROM

ADDRESS

HIGH BYTE

(80h TO 9Fh)

A DATA

EEPROM

ADDRESS

LOW BYTE

(00h TO FFh)

910

Figure 23. Single-Byte Write to EEPROM

Block Write

In this operation, the master device writes a block of data to a

slave device. The start address for a block write must have been

set previously. In the case of the ADM1026, this is done by a

Send Byte operation to set a RAM address or by a write

byte/word operation to set an EEPROM address.

The master device asserts a start condition on the SDA.

The master sends the 7-bit slave address followed by the

write bit (low).

The addressed slave device asserts an ACK on the SDA.

The master sends a command code that tells the slave

device to expect a block write. The ADM1026 command

code for a block write is A0h (10100000).

The slave asserts an ACK on the SDA.

The master sends a data byte (20h) that tells the slave

device that 32 data bytes are being sent to it. The master

should always send 32 data bytes to the ADM1026.

The slave asserts an ACK on the SDA.

The master sends 32 data bytes.

The slave asserts an ACK on the SDA after each data byte.

10. The master sends a packet error checking (PEC ) byte.

11. The ADM1026 checks the PEC byte and issues an ACK if

correct. If incorrect (NACK), the master resends the data

bytes.

12. The master asserts a stop condition on the SDA to end the

transaction.

SLAVE

ADDRESS

COMMAND

A0h BLOCK

WRITE

A DATA 1

BYTE

COUNT

DATA 2 A

DATA

PEC

Figure 24. Block Write to EEPROM or RAM

When performing a block write to EEPROM, Bit 1 of EEPROM

Unlike some EEPROM devices that limit block writes to within

a page boundary, there is no limitation on the start address

when performing a block write to EEPROM, except:

•

There must be at least 32 locations from the start address

to the highest EEPROM address (9FFF) to avoid writing to

invalid addresses.

•

If the addresses cross a page boundary, both pages must be

erased before programming.

ADM1026 Read Operations

The ADM1026 uses the SMBus read protocols described here.

Receive Byte

In this operation, the master device receives a single byte from a

slave device as follows:

The master device asserts a start condition on the SDA.

The master sends the 7-bit slave address followed by the

read bit (high).

The addressed slave device asserts an ACK on the SDA.

The master receives a data byte.

The master asserts a NO ACK on the SDA.

The master asserts a stop condition on the SDA to end the

transaction.

In the ADM1026, the receive byte protocol is used to read a

single byte of data from a RAM or EEPROM location whose

address has previously been set by a send byte or write

byte/word operation. Figure 25 shows this. When reading from

EEPROM, Bit 0 of EEPROM Register 3 must be set.

SLAVE

ADDRESS

DATA

Figure 25. Single-Byte Read from EEPROM or RAM

EVAL-ADM1026EB Datasheet(PDF) 15 Page - Analog Devices

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