Analog Devices Linear ADI Power LTM4681 Manual page 86

LTM4681
PMBus COMMAND DETAILS
The value stored in the PAGE command is not affected by PAGE_PLUS_READ. If PAGE_PLUS_READ is used to access
data from a non-paged command, the Page Number byte is ignored.
This command uses the Process Call protocol. An example of the PAGE_PLUS_READ command with PEC is shown
in Figure 54.
1
S
ADDRESS
1
SLAVE
Sr
ADDRESS
Note: PAGE_PLUS commands cannot be nested. A PAGE_PLUS command cannot be used to read or write another
PAGE_PLUS command. If this is attempted, the LTM4681 will NACK the entire PAGE_PLUS packet and issue a CML
fault for Invalid/Unsupported Data.
WRITE_PROTECT
The WRITE_PROTECT command is used to control writing to the LTM4681 device. This command does not indicate
the status of the WP pin which is defined in the MFR_COMMON command. The WP pin takes precedence over the
value of this command.
BYTE MEANING
0x80 Disable all writes except to the WRITE_PROTECT, PAGE, MFR_
EE_UNLOCK, and STORE_USER_ALL commands.
0x40 Disable all writes except to the WRITE_PROTECT, PAGE,
MFR_EE_UNLOCK, MFR_CLEAR_PEAKS, STORE_USER_ALL,
OPERATION and CLEAR_FAULTS command. Individual fault
bits can be cleared by writing a 1 to the respective bits in the
STATUS commands.
0x20 Disable all writes except to the WRITE_PROTECT, OPERATION,
MFR_EE_UNLOCK, MFR_CLEAR_PEAKS, CLEAR_FAULTS,
PAGE, ON_OFF_CONFIG, VOUT_COMMAND and STORE_USER_
ALL. Individual fault bits can be cleared by writing a 1 to the
respective bits in the STATUS commands.
0x10 Reserved, must be 0
0x08 Reserved, must be 0
0x04 Reserved, must be 0
0x02 Reserved, must be 0
0x01 Reserved, must be 0
Enable writes to all commands when WRITE_PROTECT is set to 0x00.
If WP pin is high, PAGE, OPERATION, MFR_CLEAR_PEAKS, MFR_EE_UNLOCK, WRITE_PROTECT and CLEAR_
FAULTS commands are supported. Individual fault bits can be cleared by writing a 1 to the respective bits in the
STATUS commands.
86
7 1 1 8
SLAVE PAGE_PLUS
W A
COMMAND CODE
7 1 1 8
BLOCK COUNT
R A
(= 2)
Figure 54. Example of PAGE_PLUS_READ
For more information
1 8 1 8
BLOCK COUNT PAGE
A A
(= 2) NUMBER
1 8 1 8
LOWER DATA UPPER DATA
A A
BYTE BYTE
www.analog.com
1 8 1
COMMAND
A A ...
CODE
1 8 1 1
A PEC BYTE NA P
4681 F54
Rev. A