DS2764 High-Precision Li+ Battery Monitor With 2-Wire Interface

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BL2—EEPROM Block 2 Lock Flag. A 1 in this read-only bit indicates that EEPROM block 2 (addresses 40 to 47) is

locked (read-only) while a 0 indicates block 2 is unlocked (read/write). The special order unique 64-bit ID device

does not support EEPROM Block 2.

BL1—EEPROM Block 1 Lock Flag. A 1 in this read-only bit indicates that EEPROM block 1 (addresses 30 to 3F) is

locked (read-only) while a 0 indicates block 1 is unlocked (read/write).

BL0—EEPROM Block 0 Lock Flag. A 1 in this read-only bit indicates that EEPROM block 0 (addresses 20 to 2F) is

locked (read-only) while a 0 indicates block 0 is unlocked (read/write).

X—Reserved Bits.

SPECIAL FEATURE REGISTER

The format of the special feature register is shown in Figure 14. The function of each bit is described in detail in the

following paragraphs.

Figure 14. Special Feature Register Format

ADDRESS 08

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

PS

X

X

X

X

X

SAWE

X

PS¾PS Pin Latch. This bit latches a low state on the PS pin with a 0 value. The bit is cleared only by writing a 1 to

this location. See the Power Switch Input section.

SAWE

¾Slave Address Write Enable. This bit must be set to 1 before the 2-wire slave address in location 0x32 can

be modified. SAWE should be written back to 0 after writing the slave address. Power up default is 0.

X

¾Reserved Bits.

PROGRAMMABLE SLAVE ADDRESS

The 2-Wire slave address of the DS2764 is stored in lockable EEPROM block 1, address 32h. Programming the

slave address requires a write to set the SAWE bit in the Special Feature register, followed by a write to 32h with

the desired slave address. The new slave address value is effective following the write to 32h, and must be used

to address the DS2764 on subsequent bus transactions. The slave address value is not stored to EEPROM until a

Copy EEPROM block 1 command is executed. Prior to executing the Copy command, power cycling the DS2764

restores the original slave address value. The data format of the slave address value in address 32h is shown in

Figure 15.

Figure 15. Slave Address Format

ADDRESS 32

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

A6

A5

A4

A3

A2

A1

A0

X

A6 to A0—Slave Address. A6-A0 contains the 7-bit slave address of the DS2764. The factory default is

0110100b.

X—Reserved Bits.