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dc2518af
DEMO MANUAL DC2518A
ADVANCED DEMO BOARD OPERATIONS
What is a Fault Log?
A fault log is a nonvolatile record of the power system lead-
ing up to the time of fault. Telemetry data is continuously
updated in a circular RAM buffer in the LTC2975. When a
fault occurs, the contents of the RAM buffer are automati-
cally written to NVM. The most recent monitored values
(uptime, voltage, current, temperature) provide additional
context preceding the fault. It is a powerful diagnostic
feature of the LTC2975 on the DC2518A demo board.
Create a Fault Log
To create a fault log, check that the fault_log_enable bit is
set in the MFR_CONFIG_ALL register. Then, create a fault,
as described in the section “Creating A Fault”. If multiple
boards are configured, select the appropriate device in the
system tree by clicking on the appropriate LTC2975 chip.
Working with the Fault Log
Once a fault has occurred, the Fault Log (FL) icon
will show a red (+) sign on it, indicating that the
GUI has detected a fault log in the device. Clicking
the icon will bring up a dialog box. Note that it is a context
sensitive icon. If multiple DC2518A boards are connected,
be sure that the desired device is selected in the system
tree. Notice that the EEPROM log is locked. The log will
not change until it is cleared by the user.
Reading the fault log is a 2-step process. First click the
“NVM to RAM” button. At this point the RAM Log is locked.
Click the “Read NVM Log” button. The fault log data will
appear in the text box below.
The log contains timestamp, up-time, channel voltage
readings, an input voltage reading, an on-chip temperature
reading, etc. There will be a number of loops; each loop
contains data obtained in one ADC loop time with the
most recent ADC loop data on top and the oldest data at
the bottom of the log. The up-time indicates, at the time
of fault, the amount of time the device had been powered
up or time since the previous reset.
In this case, the fault log will show that channel U0:0
faulted due to a VOUT_UV_FAULT condition. On the pre-
vious telemetry loop, the channel voltage reading was a
nominal value (+12V). You can save the fault log to a file
(.rtf) by clicking the Export button.
To clear the fault log, click the “Clear/Rearm EEPROM
Log” button. This allows the selected device to be ready
for a new fault event. To clear all faults, click the Clear
Faults (CF) icon.
