Manual

MAX15301 PMBus Command Set User’s Guide
Rev 1 Page 39 of 53
Security Commands
WRITE_PROTECT
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x10
Format:
Bit field
Data Bytes:
1
Units:
N/A
Transfer:
Read/Write Byte
Factory Value:
0x00
Description/Notes:
See Section 11.1 of the PMBus Specification Part II.
MANUF_CONF
Reference:
Maxim Specific
Lockable:
Yes
Command Code:
0xE0
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 MANUF_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 MANUF_CONF, and the read-only SECURITY_LEVEL
command is not set to level 2 by successfully sending a value of MANUF_PASSWD that matches the
working memory value of MANUF_LOCK, then the MAX15301 will ignore attempts to write data to
that command.
Note that setting a bit for a read-only PMBus command or send-byte PMBus command has no effect,
regardless of SECURITY_LEVEL. Likewise, read operations for any PMBus command are never blocked
on the basis of MANUF_CONF and SECURITY_LEVEL.
The 32 data bytes for MANUF_CONF are saved in flash memory as a unique, single instance (i.e. not
as part of the USER, DEFAULT, or MAXIM PMBus command stores.) The data is written to flash every
time the MANUF_CONF command data is written to the MAX15301.
Wait
at least 350ms for execution after sending the MANUF_CONF command before sending
additional PMBus commands.