ADM1034 datasheet(23/40 Pages) AD

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ADM1034

Rev. 0 | Page 23 of 40

FAN_FAULT OUTPUT

The FAN_FAULT output signals when one or both of the fans

stall. Pin 8, the FAN_FAULT output, is a dual-function pin. It

defaults to being a FAN_FAULT output but can be reconfigured

as an analog input reference for the THERM input. To do this,

set the FAN_FAULT/REF (Bit 7) in Configuration Register 4

(Address 0x04) to 1.

FAULT QUEUE

The ADM1034 has a programmable fault queue option that lets

the user program the number of out-of-limit measurements

allowable before generating an ALERT. The fault queue affects

only temperature measurement channels and is only operational

in SMBusALERT mode. It performs some simple filtering,

which is particularly useful at the higher conversion rates (16,

32, and 64 conversions/second), where averaging is not carried

out.

There is a queue for each of the temperature channels. If L (the

number programmed to the fault queue) or more consecutive

out-of-limit readings are made on the same temperature

channel, the fault queue fills, and the SMBusALERT output

triggers. To fill the fault queue, one needs L or more consecutive

out of limits on the internal temperature channel; L or more

consecutive out-of-limits on the external 1 temperature channel;

or L or more consecutive out-of-limits on the external 2 temp-

erature channel. The fault queue is independent of the state of

the bits in the ALERT status registers.

Table 22. Fault Queue Address 0x06

Bits <3:0>

Fault Queue

000X

001X

01XX

1XXX

To reset the fault queue, do one of the following:

•

SMBus ARA Command

•

Read Status Register 1

•

Power-On Reset

The SMBusALERT clears, even if the condition that caused the

SMBusALERT remains. The SMBusALERT is reasserted if the

fault queue fills up.

CONVERSION RATE REGISTER

The ADM1034 makes up to 64 measurements per second.

However, for the sake of reduced power consumption and better

noise immunity, users may run the ADM1034 at a slower

conversion rate. Better noise immunity results from the

averaging that occurs at the slower conversion rates. Averaging

does not occur at rates of 16, 32, or 64 conversions per second.

Table 23 lists the available conversion rates. Note that the

current round-robin loop must be finished for conversion rates

changes to take effect.

The conversion rate register is located at Address 0x05.

Table 23. Conversion Rates

Code

Conversion Rate

0x00

0.0625

0x01

0.125

0x02

0.25

0x03

0.5

0x04

0x05

0x06

0x07

0x08

0x09

0x0A

0x0B to 0xFF

Reserved

THERM I/O TIMER AND LIMITS

Pin 7 can be configured as either an input or output. As an

output it is asserted low to signal that the measured temperature

has exceeded preprogrammed temperature limits. The output is

automatically pulled high again when the temperature falls

below the THERM – Hys limit. The value of hysteresis is

programmable in Register 0x1A. THERM is enabled as an

output by default on power-up.

TEMPERATURE

LIMITS

TIME

THERM, 85

°C

THERM

THERM-HYST,

°C

Figure 33. THERM Behavior

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