LTM2987 datasheet(49/114 Pages) AD

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LTC2971

Rev. 0

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MFR_EE_UNLOCK

The MFR_EE_UNLOCK command prevents accidental EEPROM access in normal operation and configures the required

EEPROM bulk programming mode for bulk initialization, sequential writes, or reads. MFR_EE_UNLOCK augments the

protection provided by write protect. Upon unlocking the part for the required operation, an internal address pointer is

reset allowing a series of MFR_EE_DATA reads or writes to sequentially transfer data, similar to a block read or block

write. The MFR_EE_UNLOCK command can clear or set PEC mode based on the desired level of error protection. An

MFR_EE_UNLOCK sequence consists of writing two or three unlock codes as described below. The following table

documents the allowed sequences. Writing a non-supported sequence locks the part. Reading MFR_EE_UNLOCK

returns the last byte written or zero if the part is locked.

MFR_EE_UNLOCK Data Contents

BIT(S) SYMBOL

OPERATION

b[7:0] Mfr_ee_unlock[7:0] To unlock user EEPROM space for Mfr_ee_erase and Mfr_ee_data read or write operations with PEC allowed:

Write 0x2B followed by 0xD4.

To unlock user EEPROM space for Mfr_ee_erase and Mfr_ee_data read or write operations with PEC required:

Write 0x2B followed by 0xD5.

To unlock user and manufacturer EEPROM space for Mfr_ee_data read only operations with PEC allowed:

Write 0x2B, followed by 0x91 followed by 0xE4.

To unlock user and manufacturer EEPROM space for Mfr_ee_data read only operations with PEC required:

Write 0x2B, followed by 0x91 followed by 0xE5.

MFR_EE_ERASE

The MFR_EE_ERASE command is used to erase the entire contents of the user EEPROM space and configures this

space to accept new program data. Writing values other than 0x2B will lock the part. Reads return the last value written.

MFR_EE_ERASE Data contents

BIT(S) SYMBOL

OPERATION

b[7:0] Mfr_ee_erase[7:0] To erase the user EEPROM space and configure to accept new data:

1) Use the appropriate Mfr_ee_unlock sequence to configure for Mfr_ee_erase commands with or without PEC.

2) Write 0x2B to Mfr_ee_erase.

The part will indicate it is busy erasing the EEPROM by the mechanism detailed below.

MFR_EE_DATA

The MFR_EE_DATA command allows the user to transfer data directly to or from the EEPROM without affecting RAM

space.

To read the user EEPROM space issue the appropriate Mfr_ee_unlock command and perform Mfr_ee_data reads until

the EEPROM has been completely read. Extra reads will lock the part and return zero. The first read returns the 16-bit

EEPROM packing revision ID that is stored in ROM. The second read returns the number of 16-bit words available;

this is the number of reads or writes to access all memory locations. Subsequent reads return EEPROM data starting

with lowest address.

To write to the user EEPROM space issue the appropriate Mfr_ee_unlock and Mfr_ee_erase commands followed by

successive Mfr_ee_data word writes until the EEPROM is full. Extra writes will lock the part. The first write is to the

lowest address.

PMBus COMMAND DESCRIPTION

LTM2987 Datasheet(PDF) 49 Page - Analog Devices

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