Datasheet

MAX34446
PMBus Power-Supply Data Logger
19Maxim Integrated
CLEAR_FAULTS (03h)
The CLEAR_FAULTS command is used to clear any latched status bits that have been set. This command clears all
bits simultaneously. If the fault/warning is still present after the CLEAR_FAULTS command is executed, the status bit is
set again. This command is write-only. There is no data byte for this command.
WRITE_PROTECT (10h)
The WRITE_PROTECT command is used to provide protection against accidental changes to the device’s operating
memory. All supported commands can have their parameters read, regardless of the WRITE_PROTECT settings. Table 5
describes the WRITE_PROTECT message content.
Table 5. WRITE_PROTECT Command Byte
Note: No fault or error is generated if the host attempts to write to a protected area.
Table 6. CAPABILITY Command Byte
STORE_DEFAULT_ALL (11h)
The STORE_DEFAULT_ALL command instructs the device to transfer the device configuration information to the internal
flash memory array. Not all information is stored. Only configuration data is stored, not any status, or operational data.
If an error occurs during the transfer, the CML bit is set to 1. The device is unresponsive to PMBus commands while
transferring the configuration. This command is write-only. There is no data byte for this command. After this command
is sent, another command should not be sent for at least 250ms.
RESTORE_DEFAULT_ALL (12h)
The RESTORE_DEFAULT_ALL command transfers the default configuration information from the internal flash memory
array to the user memory registers in the device. Upon a device power-on reset or device reset through the RST input
pin, this command is automatically executed by the device without PMBus action required. This command is write-only.
There is no data byte for this command. There is no data byte for this command. After this command is sent, another
command should not be sent for at least 250ms.
CAPABILITY (19h)
The CAPABILITY command is used to determine some key capabilities of the device. The CAPABILITY command is
read-only. Table 6 describes the message content.
COMMAND BYTE MEANING
80h Disable all writes except the WRITE_PROTECT command.
40h Disable all writes except the WRITE_PROTECT and PAGE commands.
00h Enable writes for all commands (default).
BIT DESCRIPTION MEANING
7 Packet-Error Checking 0 = PEC not supported.
6:5 PMBus Speed 00 = Maximum supported bus speed is 100kHz.
4 ALERT 0 = Device does not support ALERT output.
3:0 Reserved Always returns 0000.