ADT7483A

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11

Table 12. STATUS REGISTER 1 BIT ASSIGNMENTS

Bit

Mnemonic

Function

ALERT

7

BUSY

1 when ADC Converting

No

6

LHIGH

(Note 1)

1 when Local High

Temperature Limit Tripped

Yes

5

LLOW

(Note 1)

1 when Local Low

Temperature Limit Tripped

Yes

4

R1HIGH

(Note 1)

1 when Remote 1 High

Temperature Limit Tripped

Yes

3

R1LOW

(Note 1)

1 when Remote 1 Low

Temperature Limit Tripped

Yes

2

D1 OPEN

(Note 1)

1 when Remote 1 Sensor

Open Circuit

Yes

1

R1THRM1

1 when Remote1 THERM

Limit Tripped

No

0

LTHRM1

1 when Local THERM Limit

Tripped

No

1. These flags stay high until the status register is read, or they are

reset by POR.

Table 13. STATUS REGISTER 2 BIT ASSIGNMENTS

Bit

Mnemonic

Function

ALERT

7

Res

Reserved for Future Use

No

6

Res

Reserved for Future Use

No

5

Res

Reserved for Future Use

No

4

R2HIGH

(Note 1)

1 when Remote 2 High

Temperature Limit Tripped

Yes

3

R2LOW

(Note 1)

1 when Remote 2 Low

Temperature Limit Tripped

Yes

2

D2 OPEN

(Note 1)

1 when Remote 2 Sensor

Open Circuit

Yes

1

R2THRM1

1 when Remote 2 THERM

Limit Tripped

No

0

ALERT

1 when ALERT Condition

Exists

No

1. These flags stay high until the status register is read, or they are

reset by POR.

The eight flags that can generate an ALERT are NOR’d

together, so if any of them are high, the ALERT interrupt

latch is set and the ALERT output goes low (provided they

are not masked out).

Reading the Status 1 register will clear the five flags, Bit 6

to Bit 2 in Status Register 1, provided the error conditions

that caused the flags to be set have gone away. Reading the

Status 2 register will clear the three flags, Bit 4 to Bit 2 in

Status Register 2, provided the error conditions that caused

the flags to be set have gone away. A flag bit can only be reset

if the corresponding value register contains an in-limit

measurement or if the sensor is good.

The ALERT interrupt latch is not reset by reading the

status register. It is reset when the ALERT output has been

serviced by the master reading the device address, provided

the error condition has gone away and the status register flag

bits have been reset.

When Flag 1 and/or Flag 0 of Status Register 1, or Flag 1

of Status Register 2 are set, the THERM output goes low to

indicate that the temperature measurements are outside the

programmed limits. The THERM output does not need to be

reset, unlike the ALERT output. Once the measurements are

within the limits, the corresponding status register bits are

automatically reset and the THERM output goes high. The

user may add hysteresis by programming Register 0x21.

The THERM output will be reset only when the temperature

falls below the THERM limit minus hysteresis.

When Pin 13 is configured as THERM2, only the high

temperature limits are relevant. If Flag 6, Flag 4 of Status

Register 1, or Flag 4 of Status Register 2 are set, the

THERM2 output goes low to indicate that the temperature

measurements are outside the programmed limits. Flag 5

and Flag 3 of Status Register 1, and Flag 3 of Status

Register 2 have no effect on THERM2. The behavior of

THERM2 is otherwise the same as THERM.

Bit 0 of Status Register 2 is set whenever the ALERT

output of the ADT7483A is asserted low. This means that the

user need only read Status Register 2 to determine if the

ADT7483A is responsible for the ALERT. Bit 0 of Status

Register 2 is reset when the ALERT output is reset. If the

ALERT output is masked, then this bit is not set.

Offset Register

Offset errors may be introduced into the remote

temperature measurement by clock noise or by the thermal

diode being located away from the hot spot. To achieve the

specified accuracy on this channel, these offsets must be

removed.

The offset values are stored as 10-bit, twos complement

values:

and the LSBs are stored 0x12 (low byte, left justified).

and the LSBs are stored 0x35 (low byte, left justified).

The Remote 2 offset can be written to, or read from, the

Remote 1 offset registers if Bit 3 of the Configuration 1

register is set to 1. This bit should be set to 0 (default)

to read the Remote 1 offset values.

Only the upper 2 bits of the LSB registers are used. The

MSB of the MSB offset registers is the sign bit. The

minimum offset that can be programmed is −128C, and the

maximum is +127.75C.

The value in the offset register is added or subtracted to the

measured value of the remote temperature.

The offset register powers up with a default value of 0C

and will have no effect unless the user writes a different

value to it.