Datasheet

Alert Mask D8h
From PMBus
From other
fault inputs
ARA Auto Mask
Set
Clear
Fault Condition
ARA Operation Flag Succeeded
Clear_Fault Command Received
SMBA
LM5066
SNVS655G –JUNE 2011–REVISED FEBRUARY 2013 www.ti.com
SMBA RESPONSE
The SMBA effectively has two masks:
1. The Alert Mask Register at D8h, and
2. The ARA Automatic Mask.
The ARA Automatic Mask is a mask that is set in response to a successful ARA read. An ARA read operation
returns the PMBus address of the lowest addressed part on the bus that has its SMBA asserted. A successful
ARA read means that THIS part was the one that returned its address. When a part responds to the ARA read, it
releases the SMBA signal. When the last part on the bus that has an SMBA set has successfully reported its
address, the SMBA signal will de-assert.
The way that the LM5066 releases the SMBA signal is by setting the ARA Automatic mask bit for all fault
conditions present at the time of the ARA read. All status registers will still show the fault condition, but it will not
generate and SMBA on that fault again until the ARA Automatic mask is cleared by the host issuing a
CLEAR_FAULTS command to this part. This should be done as a routine part of servicing an SMBA condition on
a part, even if the ARA read is not done. Figure 20 depicts a schematic version of this flow.
Figure 20. Typical Flow Schematic for SMBA Fault
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