ADT7516 datasheet(28/44 Pages) AD

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ADT7516/ADT7517/ADT7519

Rev. A | Page 28 of 44

Table 9. Temperature Data Format (Internal and External

Temperature)

Temperature

Digital Output

–40°C

11 0110 0000

–25°C

11 1001 1100

–10°C

11 1101 1000

–0.25°C

11 1111 1111

0°C

00 0000 0000

+0.25°C

00 0000 0001

+10°C

00 0010 1000

+25°C

00 0110 0100

+50°C

00 1100 1000

+75°C

01 0010 1100

+100°C

01 1001 0000

+105°C

01 1010 0100

+125°C

01 1111 0100

Temperature conversion formula:

Positive Temperature = ADC Code/4

Negative Temperature = (ADC Code* – 512)/4

*where DB9 is removed from the ADC code.

Interrupts

The measured results from the internal temperature sensor,

external temperature sensor, VDD pin, and AIN inputs are

compared with the THIGH/VHIGH (greater than comparison) and

TLOW/VLOW (less than or equal to comparison) limits. An inter-

rupt occurs if the measurement exceeds or equals the limit

registers. These limits are stored in on-chip registers. Note that

the limit registers are 8 bits long while the conversion results are

10 bits long. If the limits are not masked, any out-of-limit com-

parisons generate flags that are stored in the Interrupt Status 1

(Address 01h). One or more out-of-limit results will cause the

INT/INT output to pull either high or low depending on the

output polarity setting. It is good design practice to mask out

interrupts for channels that are of no concern to the application.

Figure 53 shows the interrupt structure for the ADT7516/

ADT7517/ADT7519. It gives a block diagram representation of

how the various measurement channels affect the INT/INT pin.

ADT7516/ADT7517/ADT7519 REGISTERS

The ADT7516/ADT7517/ADT7519 contain registers that are

used to store the results of external and internal temperature

measurements, VDD value measurements, analog input measure-

ments, high and low temperature limits, supply voltage and

analog input limits, set output DAC voltage levels, configure

multipurpose pins, and generally to control the device. A

description of these registers follows.

The register map is divided into registers of 8 bits. Each register

has its own individual address, but some consist of data that is

linked with other registers. These registers hold the 10-bit

conversion results of measurements taken on the temperature,

VDD, and AIN channels. For example, the eight MSBs of the VDD

measurement are stored in register Address 06h while the two

LSBs are stored in register Address 03h. The link involved

between these types of registers is that when the LSB register is

read first, the MSB registers associated with that LSB register are

locked to prevent any updates. To unlock these MSB registers,

the user has only to read any one of them, which will have the

effect of unlocking all previously locked MSB registers. So for

the preceding example, if Register 03h was read first, MSB

Registers 06h and 07h would be locked to prevent any updates

to them. If Register 06h was read, this register and Register 07h

would be subsequently unlocked.

LOCK ASSOCIATED

MSB REGISTERS

FIRST READ

COMMAND

LSB

OUTPUT

DATA

Figure 55. Phase 1 of 10-Bit Read

UNLOCK ASSOCIATED

MSB REGISTERS

SECOND READ

COMMAND

MSB

OUTPUT

DATA

Figure 56. Phase 2 of 10-Bit Read

If an MSB register is read first, its corresponding LSB register is

not locked, leaving the user with the option of just reading back

8 bits (MSB) of a 10-bit conversion result. Reading an MSB

reading an LSB register first does not lock other LSB registers.

Table 10. ADT7516/ADT7517/ADT7519 Registers

RD/WR

Address

Name

Power-On

Default

00h

Interrupt Status 1

00h

01h

Interrupt Status 2

00h

02h

Reserved

03h

Internal Temp and VDD LSBs

00h

04h

External Temp and AIN1 to

AIN4 LSBs

00h

05h

Reserved

00h

06h

VDD MSBs

xxh

07h

Internal Temp MSBs

00h

08h

External Temp MSBs/AIN1

MSBs

00h

09h

AIN2 MSBs

00h

0Ah

AIN3 MSBs

00h

0Bh

AIN4 MSBs

00h

0Ch–0Fh

Reserved

00h

10h

DAC A LSBs

(ADT7516/ADT7517 only)

00h

11h

DAC A MSBs

00h

12h

DAC B LSBs

(ADT7516/ADT7517 only)

00h

13h

DAC B MSBs

00h

14h

DAC C LSBs

(ADT7516/ADT7517 only)

00h

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