107
Rev. B
would still set bit 6 of STATUS_TEMPERATURE but not assert
ALERT
. All other supported STATUS_TEMPERATURE
bits would continue to assert
ALERT
if set.
Figure 50 shows an example of the Block Write – Block Read Process Call protocol used to read back the present state
of any supported status register, again without PEC.
SMBALERT_MASK cannot be applied to STATUS_BYTE, STATUS_WORD, MFR_COMMON or MFR_PADS_LTM4680.
Factory default masking for applicable status registers is shown below. Providing an unsupported command code to
SMBALERT_MASK will generate a CML for Invalid/Unsupported Data.
SMBALERT_MASK Default Setting: (Refer Also to Figure 2)
STATUS RESISTER
ALERT Mask Value MASKED BITS
STATUS_VOUT
0x00
None
STATUS_IOUT
0x00
None
STATUS_TEMPERATURE
0x00
None
STATUS_CML
0x00
None
STATUS_INPUT
0x00
None
STATUS_MFR_SPECIFIC
0x11
Bit 4 (internal PLL unlocked), bit 0 (
FAULT
pulled low by external device)
PMBus COMMAND DETAILS
SLAVE
ADDRESS
SMBALERT_MASK
COMMAND CODE
BLOCK COUNT
(= 1)
W A
A
S
7
8
8
1
STATUS_x
COMMAND CODE
8
1
1 1
1
1
A
A
…
Sr
1
BLOCK COUNT
(= 1)
A
NA P
4680 F53
A
8
8
1
1 1
1
MASK BYTE
SLAVE
ADDRESS
7
R
1
P
1
SLAVE
ADDRESS
SMBALERT_MASK
COMMAND CODE
STATUS_x
COMMAND CODE
W A
A
S
7
8
8
1
8
1
1 1
1
1
A
A
MASK BYTE
4680 F52
Figure 52. Example of Writing SMBALERT_MASK
Figure 53. Example of Reading SMBALERT_MASK
MFR_CLEAR_PEAKS
The MFR_CLEAR_PEAKS command clears the MFR_*_PEAK data values. A MFR_RESET command will also clear the
MFR_*_PEAK data values.
This write-only command has no data bytes.
STATUS_BYTE
The STATUS_BYTE command returns one byte of information with a summary of the most critical faults. This is the
lower byte of the status word.
