Finisar AN-2030 Password Addresses 2-Wire Address A2h, User Eeprom 2-Wire Address A2h

AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers F i n i s a r

Bytes 123 – 126 contain write-only RAM for entry of a 32 bit password that allows access to user writable EEPROM at locations 128-247. The default password for Finisar devices is 0, however it can be set to any value at the factory to insure security of the user writable EEPROM contents. Please contact your Finisar sales representative for details on setting up a custom password. Once the password has been entered into locations 123 – 126, a ‘1’ should be written to address 127 (readable and writeable RAM cell). Note that the power-on default value of byte 127 is ‘0’. Once these two steps have been completed, EEPROM at locations 128 – 247 is readable and writable. The EEPROM remains readable and writable until either the password is changed or byte 127 is set to 0.

Table 3.19: Password Addresses (2-Wire Address A2h)

Byte	Bit	Name	Description
120-122	All	Reserved	Reserved
123	All	Password Byte 3	High order byte of 32 bit password
124	All	Password Byte 2	Second highest order byte of 32 bit password
125	All	Password Byte 1	Second lowest byte of 32 bit password
126	All	Password Byte 0	Low order byte of 32 bit password
127	All	User EEPROM Select	‘1’ selects user writable EEPROM at locations 128 - 247

Bytes 128 – 247 contain user readable/writable EEPROM that is accessed following the steps outlined above. Bytes 248 – 255 are reserved for control functions and should not be written.

Table 3.20: User EEPROM (2-Wire Address A2h)

Address	# Bytes	Name	Description
128-247	120	User EEPROM	User-writable/readable EEPROM
248-255	8	Vendor Specific	Vendor specific control functions

9/26/02 Revision D Page 27