DS1864 datasheet(41/72 Pages) DALLAS

41 / 72 page

SFP Laser Controller and

Diagnostic IC

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Lower Memory Register 7Bh to 7Eh: Password Entry Bytes

POWER-ON VALUE:

0000 0000h

MEMORY TYPE:

Volatile (SRAM)

7Bh

7Ch

7Dh

7Eh

bit7

bit0

The password is entered into the four bytes to gain PW1 or PW2 level access. There are two levels of passwords for the DS1864.

The lower level password (PW1) will have access to unprotected areas plus those made available with PW1. The higher level

password (PW2) will have all of the access of PW1 plus those made available with PW2. See the Memory Protection section for

details on password access.

Lower Memory Register 7Fh: Table Select Byte

POWER-ON VALUE:

See below

MEMORY TYPE:

Volatile (SRAM)

7Fh

000

bit7

bit0

The upper memory tables of the DS1864 are selected by writing the desired Table value in this register. For example, if Table 04h is

to be selected, the value 04h will be written to register 7Fh. The Power On value of the Table Select Byte is determined by the value

written in Table 04h (Table 01h in DS1859 configuration), register C7h.

Table 01h (Table 00h in DS1859 Configuration), 80h to F7h: User Memory

FACTORY DEFAULT:

00h

MEMORY TYPE:

Nonvolatile (EEPROM)

80h to F7h

EEPROM

bit7

bit0

This is general use EEPROM.

Table 01h In Default DS1852 Configuration, (Table 00h in DS1859 Configuration)

DS1864 Datasheet(PDF) 41 Page - Dallas Semiconductor