ADM1023ARQZ-REEL 데이터 시트보기 (PDF) - ON Semiconductor

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ADM1023ARQZ-REEL

ACPI-Compliant, High Accuracy Microprocessor System Temperature Monitor

ON Semiconductor 

ADM1023

Table 5. Status Register Bit Assignments

Bit

Name

Function

7

BUSY At 1 when ADC converting

6

LHIGH* At 1 when local high temp limit tripped

5

LLOW* At 1 when local low temp limit tripped

4

RHIGH* At 1 when remote high temp limit tripped

3

RLOW* At 1 when remote low temp limit tripped

2

OPEN* At 1 when remote sensor open−circuit

1 to 0

Reserved

*These flags stay high until the status register is read or they are

reset by POR.

Configuration Register

Two bits of the configuration register are used. If Bit 6 is 0,

which is the power−on default, the device is in operating

mode with the ADC converting (see Table 6). If Bit 6 is set

to 1, the device is in standby mode and the ADC does not

convert. Standby mode can also be selected by taking the

STBY pin low. In standby mode, the values of remote and

local temperature remain at the value they were before the

part was placed in standby mode.

Bit 7 of the configuration register is used to mask the

ALERT output. If Bit 7 is 0, which is the power−on default,

the ALERT output is enabled. If Bit 7 is set to 1, the ALERT

output is disabled.

Table 6. Configuration Register Bit Assignments

Bit

Name

Function

Power−On

Default

7

MASK1

0 = ALERT Enabled

0

1 = ALERT Masked

6

RUN/STOP 0 = Run

0

1 = Standby

5 to 0

Reserved

0

Conversion Rate Register

The lowest three bits of this register are used to program

the conversion rate by dividing the ADC clock by 1, 2, 4, 8,

16, 32, 64, or 128, to give conversion times from 125 ms

(Code 0x07) to 16 seconds (Code 0x00). This register can be

written to and read back over the SMBus. The higher five

bits of this register are unused and must be set to 0. Use of

slower conversion times greatly reduces the device’s power

consumption, as shown in Table 7.

Table 7. Conversion Rate Register Code

Data

Conversion/Sec

Average Supply Current

mA Typ at VCC = 3.3 V

0x00

0.0625

150

0x01

0.125

150

0x02

0.25

150

0x03

0.5

150

0x04

1

150

0x05

2

150

0x06

4

160

0x07

8

180

0x08 to

0xFF

Reserved

Limit Registers

The ADM1023 has six limit registers to store local and

remote, high and low temperature limits. These registers can

be written to and read back over the SMBus. The high limit

registers perform a > comparison, while the low limit

registers perform a < comparison. For example, if the high

limit register is programmed as a limit of 80°C, measuring

81°C results in an alarm condition. Even though the

temperature range is 0 to 127°C, it is possible to program the

limit register with negative values. This is for

backward−compatibility with the ADM1021.

One−Shot Register

The one−shot register is used to initiate a single

conversion and comparison cycle when the ADM1023 is in

standby mode, after which the device returns to standby.

This is not a data register as such, and it is the write operation

that causes the one−shot conversion. The data written to this

address is irrelevant and is not stored.

Serial Bus Interface

Control of the ADM1023 is carried out via the serial bus.

The ADM1023 is connected to this bus as a slave device,

under the control of a master device. Note that the SMBus

SDA and SCLK pins are three−stated when the ADM1023

is powered down, and they do not pull down the SMBus.

Address Pins

In general, every SMBus device has a 7−bit device address

(except for some devices that have extended, 10−bit

addresses). When the master device sends a device address

over the bus, the slave device with that address responds.

The ADM1023 has two address pins, ADD0 and ADD1, to

allow selection of the device address, so that several

ADM1023s can be used on the same bus and to avoid

conflict with other devices. Although only two address pins

are provided, these pins are three−state and can be grounded,

left unconnected, or tied to VDD, so that a total of nine

different addresses are possible, as shown in Table 8.

Note that the state of the address pins is sampled only at

powerup, so changing them after powerup has no effect.

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