ADT7320

Preliminary Technical Data

Rev. PrA | Page 12 of 24

CONTINUOUS READ MODE

When the command byte = 01010100 (0x54), the contents of

the temperature value register can be read out without requiring

repeated writes to the communications register. By sending 16

SCLK clocks to the ADT7320, the contents of the temperature

value register are output onto the DOUT pin.

To exit the continuous read mode, the command byte 01010000

(0x50) must be written to the ADT7320.

While in continuous read mode, the part monitors activity

on the DIN line so that it can receive the instruction to exit

the continuous read mode. Additionally, a reset occurs if 32

consecutive 1s are seen on the DIN pin. Therefore, hold DIN

low in continuous read mode until an instruction is to be

written to the device.

In continuous read mode, the temperature value register cannot

be read when a conversion is taking place. If an attempt is made

to read the temperature value register while a conversion is taking

place, then all 0s are read. This is because the continuous read

mode blocks read access to the temperature value register during a

conversion.

SHUTDOWN

The ADT7320 can be placed in shutdown mode by writing 1

to Bit 5 and 1 to Bit 6 of the configuration register (Register

Address 0x01). The ADT7320 can be taken out of shutdown

mode by writing 0 to Bit 5 and 0 to Bit 6 of the configuration

register (Register Address 0x01). The ADT7320 typically takes

1 ms (with a 0.1 μF decoupling capacitor) to come out of shut-

down mode. The conversion result from the last conversion

prior to shutdown can still be read from the ADT7320 even

when it is in shutdown mode. When the part is taken out of

shutdown mode, the internal clock starts and a conversion initiates.

FAULT QUEUE

Bit 0 and Bit 1 of the configuration register (Register Address 0x01)

are used to set up a fault queue. Up to four faults are provided to

prevent false tripping of the INT and CT pins when the ADT7320

is used in a noisy temperature environment. The number of

faults set in the queue must occur consecutively to set the INT

and CT outputs. For example, if the number of faults set in the

queue is four, then four consecutive temperature conversions

must occur, with each result exceeding a temperature limit in

any of the limit registers, before the INT and CT pins are activated.

If two consecutive temperature conversions exceed a temperature

limit and the third conversion does not, the fault count is reset to 0.

DIN

0x54

SCLK

DOUT

CS

TEMPERATURE

VALUE

TEMPERATURE

VALUE

TEMPERATURE

VALUE

Figure 14. Continuous Read Mode