ADT7483AARQZ-R7 datasheet(14/24 Pages) ONSEMI

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ADT7483A

Rev. 1 | Page 14 of 24 | www.onsemi.com

Status Registers

The status registers are read-only registers, at Address 0x02

(Status Register 1) and Address 0x23 (Status Register 2). They

contain status information for the ADT7483A.

Table 11. Status Register 1 Bit Assignments

Bit

Mnemonic

Function

ALERT

BUSY

Bit set to 1 when ADC converting

LHIGH1

Bit set to 1 when local high

temperature limit tripped

Yes

LLOW1

Bit set to 1 when local low

temperature limit tripped

Yes

R1HIGH1

Bit set to 1 when remote 1 high

temperature limit tripped

Yes

R1LOW1

Bit set to 1 when remote 1 low

temperature limit tripped

Yes

D1 OPEN1

Bit set to 1 when remote 1 sensor

open circuit

Yes

R1THRM1

Bit set to 1 when remote1 THERM

limit tripped

LTHRM1

Bit set to 1 when local THERM limit

tripped

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

Table 12. Status Register 2 Bit Assignments

Bit

Mnemonic

Function

ALERT

Res

Reserved for future use

Res

Reserved for future use

Res

Reserved for future use

R2HIGH1

Bit set to 1 when Remote 2 high

temperature limit tripped

Yes

R2LOW1

Bit set to 1 when Remote 2 low

temperature limit tripped

Yes

D2 OPEN1

Bit set to 1 when Remote 2 sensor

open circuit

Yes

R2THRM1

Bit set to 1 when Remote2 THERM

limit tripped

ALERT

Bit set to 1 when ALERT condition

exists

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

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

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

output goes low to indicate that the temperature measurements

are outside the programmed limits. Flag 5 and Flag 3 of Status

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.

The Remote 1 offset MSBs are stored in Register 0x11, and the

LSBs are stored 0x12 (low byte, left justified). The Remote 2

offset MSBs are stored in Register 0x34, 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.

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