MAX34446_12 Datasheet, PDF (30/36 Pages) Maxim Integrated Products – PMBus Power-Supply Data Logger

MAX34446
PMBus Power-Supply Data Logger
MFR_NV_FAULT_LOG (DCh)
Each time the MFR_NV_FAULT_LOG command is executed, the device returns a block of 255 bytes containing one of
the 64 nonvolatile fault logs. The MFR_NV_FAULT_LOG command must be executed 64 times to dump the complete
nonvolatile fault log. If the returned fault log contains all FFh, this indicates that the fault log has not been written by the
device. As the device is operating, it is reading the latest operating conditions for voltage, current, and temperature and
it is updating the status registers. All of this information is stored in on-board RAM. When a fault/warning is detected (if
so enabled in MFR_FAULT_RESPONSE), the device automatically logs this information to one of the 64 nonvolatile fault
logs. After 64 fault logs are written, bit 0 of STATUS_CML is set and the device can be configured (with the NV_LOG_
OVERWRITE bit in MFR_MODE) to either stop writing additional fault logs or to write over the oldest data. The host can
clear the fault log by setting the CLEAR_NV_FAULT_LOG bit in MFR_MODE.
All the latest status, temperature, and peak/minimum excursion information is logged. Also, 160 bytes of the 255-byte
log are dedicated to report the latest ADC readings of voltage and current. The number of readings per ADC channels
depends on the number of channels enabled. See Table 18. Also, the LOGSKIP bits in the MFR_MODE command can
be used to allow the device to only log every 2nd, 4th, or 8th reading so that the fault log can record data over a longer
time frame (see Table 16).
Table 18. MFR_NV_FAULT_LOG 160-Byte Running Voltage/Current Log Format
1 CHANNEL ENABLED
80 Readings for ADC0,
Data Buffer 0 to 79
2 CHANNELS ENABLED
40 Readings for ADC0,
Data Buffer 0 to 39
40 Readings for ADC1,
Data Buffer 40 to 79
4 CHANNELS ENABLED
20 Readings for ADC0, Data Buffer 0 to 19
20 Readings for ADC1, Data Buffer 20 to 39
20 Readings for ADC2, Data Buffer 40 to 59
20 Readings for ADC3, Data Buffer 60 to 79
Note: The number of ADC channels is configured with the CHANNEL bits in the MFR_MODE command.
RAM
STATUS_BYTE
STATUS_WORD
STATUS_VOUT
STATUS_CML
STATUS_MFR_SPECIFIC
MFR_VOUT_PEAK
MFR_IOUT_PEAK
MFR_TEMPERATURE_PEAK
MFR_VOUT_MIN
MFR_TIME_COUNT
MFR_POUT_PEAK
MFR_POUT_AVG
MFR_IOUT_AVG
MFR_TEMPERATURE_AVG
READ_TEMPERATURE_1
EACH FAULT IS
WRITTEN INTO THE
NEXT FAULT LOG
FAULT OR
WARNING
OCCURRENCE
READ_VOUT OR READ_IOUT
(LATEST 20, 40, OR 80 READINGS)
FLASH
FAULT LOG INDEX 0
(255 BYTES)
FAULT LOG INDEX 1
(255 BYTES)
FAULT LOG INDEX 2
(255 BYTES)
EACH COMMAND READ
ACCESSES THE NEXT FAULT LOG
MFR_NV_FAULT_LOG
FAULT LOG INDEX 63
(255 BYTES)
NOTE: AFTER DEVICE POWER-UP OR RESET, AT LEAST ONE NONFAULTY READING MUST OCCUR BEFORE A NEW FAULT LOG OCCURS.
Figure 4. NV Fault Logging Arrangement
Maxim Integrated
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