LTC3882-1
70
Rev A
For more information
Figure 50. Example of PAGE_PLUS_READ
WRITE_PROTECT
The WRITE_PROTECT command is used to control PMBus write access to the LTC3882-1.
Supported Values:
VALUE
MEANING
0x80
Disable all writes except WRITE_PROTECT, PAGE, STORE_USER_ALL and MFR_EE_UNLOCK commands.
0x40
Disable all writes except WRITE_PROTECT, PAGE, STORE_USER_ALL, MFR_EE_UNLOCK, OPERATION, CLEAR_PEAKS and CLEAR_FAULTS
commands. Individual faults can also be cleared by writing a 1 to the respective status bit.
0x20
Disable all writes except WRITE_PROTECT, PAGE, STORE_USER_ ALL, MFR_EE_UNLOCK, OPERATION, CLEAR_PEAKS, CLEAR_FAULTS,
ON_OFF_CONFIG and VOUT_COMMAND commands. Individual faults can be cleared by writing a 1 to the respective status bit.
0x00
Enables writes to all commands.
This command has one data byte.
P
1
SLAVE
ADDRESS
PAGE_PLUS
COMMAND CODE
BLOCK COUNT
(= 2)
W A
A
S
7
8
8
1
PAGE
NUMBER
8
1
1 1
1
1
A
A
…
COMMAND
CODE
8
1
A
SLAVE
ADDRESS
BLOCK COUNT
(= 2)
LOWER DATA
BYTE
R A
A
Sr
7
8
8
1
UPPER DATA
BYTE
8
1
1 1
1
1
A
A
PEC BYTE
8
1
NA
38821 F50
PMBus COMMAND DETAILS
(Addressing and Write Protect)
PAGE_PLUS_READ
The PAGE_PLUS_READ command provides the ability to set the page within a device, send a command and then read
the data returned by the command, all in one communication packet .
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 Block Write – Block Read Process Call protocol. An example of the PAGE_PLUS_READ command
with PEC is shown in Figure 50.
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 LTC3882-1 will NACK the entire PAGE_PLUS packet and issue a CML
fault for Invalid/Unsupported Data.
