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Manuf_lock, Manuf_passwd, User_conf – Maxim Integrated MAX15301 PMBus Command Set User Manual

Page 40

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MAX15301 PMBus Command Set User’s Guide

Rev 1

Page 40 of 53

MANUF_LOCK

Reference:

Maxim Specific

Lockable:

Yes

Command Code:

0xE1

Format:

Direct

Data Bytes:

2

Units:

N/A

Transfer:

Write Word

Factory Value:

0x0000

Description/Notes:

The MANUF_LOCK command contains the password value for the “manufacturer” PMBus command
security level. If the working-memory value of

MANUF_PASSWD

matches the working-memory value

of MANUF_LOCK, the

SECURITY_LEVEL

value is set to 2, and any PMBus commands flagged in

MANUF_CONF

or

USER_CONF

are unlocked for write operations.

Note that SECURITY_LEVEL must be set to 2 before a new value can be written to MANUF_LOCK.

The value of MANUF_LOCK can be stored in both the USER and DEFAULT nonvolatile PMBus memory
with separate and distinct values – this should be taken into account when setting up command
security.

MANUF_PASSWD

Reference:

Maxim Specific

Lockable:

Yes

Command Code:

0xE2

Format:

Direct

Data Bytes:

2

Units:

N/A

Transfer:

Read/Write Word

Factory Value:

N/A

Description/Notes:

The MANUF_PASSWD command is the “key” or password-attempt command used to unlock the
“manufacturer” security level. If the working-memory value of MANUF_PASSWD matches the
working-memory value of

MANUF_LOCK

, the

SECURITY_LEVEL

value is set to 2, and any PMBus

commands flagged in

MANUF_CONF

or

USER_CONF

are unlocked for write operations.

The value of MANUF_PASSWD is only retained in working memory and cannot be stored.

USER_CONF

Reference:

Maxim Specific

Lockable:

Yes

Command Code:

0xE3

Format:

Bit field

Data Bytes:

32

Units:

N/A

Transfer:

Read/Write Block

Factory Value:

0

Description/Notes:

To allow password-based write-protection on a per-command basis, the USER_CONF command has
32 data bytes, with one bit per possible PMBus command; the byte order is low to high. Each bit
position within the 32 bytes correlates to a PMBus command number from 0x00 to 0xFF. For
example:

Byte 0, bit 0: PAGE command
Byte 0, bit 1: OPERATION command
Byte 0, bit 2: ON_OFF_CONFIG command

Byte 6, bit 3: FREQUENCY_SWITCH command
etc…

If the bit for a particular command is set in USER_CONF, and the read-only

SECURITY_LEVEL

command

is not set to level 1 by successfully sending a value of

USER_PASSWD

that matches the working