MAX16065 Datasheet, PDF(26/61 Page) Maxim Integrated Products – 12-Channel/8-Channel, Flash-Configurable System Managers with Nonvolatile Fault Registers

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12-Channel/8-Channel, Flash-Configurable System

Managers with Nonvolatile Fault Registers

External Fault (EXTFAULT)

GPIO4 and GPIO8 are configurable as the external fault

input/output. When configured as push-pull, EXTFAULT

signals that a critical fault has occurred on one or more

monitored voltages or current. When configured as

open-drain, EXTFAULT can be asserted low by an exter-

nal circuit to trigger a critical fault. This signal can be

used to cascade multiple MAX16065/MAX16066s.

Two configuration bits determine the behavior of the

MAX16065/MAX16066 when EXTFAULT is pulled low

by some other device. Register bit r72h[5], if set to a

â1â, causes the sequencer state machine to enter the

fault state, deasserting all the outputs, when EXTFAULT

is pulled low. When this happens, the flag bit r1Ch[5]

gets set to indicate the cause of the fault. If register bit

r6Dh[2] is set in addition to r72h[5], EXTFAULT going low

triggers a nonvolatile fault log operation.

Faults

The MAX16065/MAX16066 monitor the input (MON_)

channels and compare the results with an overvoltage

threshold, an undervoltage threshold, and a selectable

overvoltage or undervoltage early warning threshold.

Based on these conditions, the MAX16065/MAX16066

assert various fault outputs and save specific informa-

tion about the channel conditions and voltages into the

nonvolatile flash. Once a critical fault event occurs, the

failing channel condition, ADC conversions at the time of

the fault, or both can be saved by configuring the event

logger. The event logger records a single failure in the

internal flash and sets a lock bit that protects the stored

fault data from accidental erasure on a subsequent

power-up.

An overvoltage event occurs when the voltage at a moni-

tored input exceeds the overvoltage threshold for that

input. An undervoltage event occurs when the voltage

at a monitored input falls below the undervoltage thresh-

old. Fault thresholds are set in registers r48h to r6Ch as

shown in Table 15. Disabled inputs are not monitored for

fault conditions and are skipped over by the input mul-

tiplexer. Only the upper 8 bits of a conversion result are

compared with the programmed fault thresholds.

The general-purpose inputs/outputs (GPIO1 to GPIO8)

can be configured as ANY_FAULT outputs or dedicated

Fault1 and Fault2 outputs to indicate fault conditions.

These fault outputs are not masked by the critical fault

enable bits shown in Table 18. See the General-Purpose

Inputs/Outputs section for more information on configur-

ing GPIO_s as fault outputs.

Deglitch

Fault conditions are detected at the end of each conver-

sion. When the voltage on an input falls outside a moni-

tored threshold for one acquisition, the input multiplexer

remains on that channel and performs several succes-

sive conversions. To trigger a fault, the input must stay

outside the threshold for a certain number of acquisitions

as determined by the deglitch setting in r73h[6:5] and

r74h[6:5] (see Table 16).

Fault Flags

Fault flags indicate the fault status of a particular input.

The fault flag of any monitored input in the device can be

read at any time from registers r1Bh and r1Ch, as shown

in Table 17. Clear a fault flag by writing a â1â to the appro-

priate bit in the flag register. Unlike the fault signals sent

to the fault outputs, these bits are masked by the critical

fault enable bits (see Table 18). The fault flag is only set

when the matching enable bit in the critical fault enable

If a GPIO_ is configured as an open-drain EXTFAULT

input/output, and EXTFAULT is pulled low by an external

circuit, bit r1Ch[5] is set.

If a fault occurs during the secondary sequence group,

the slot number where the failure occurred is stored

in r1Dh.

The SMBus Alert bit is set if the MAX16065/MAX16066

have asserted the SMBus Alert output. Clear by writing a

â1â. See the SMBALERT section for more details.

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