AT30TS750A_14 Datasheet, PDF (27/48 Pages) ATMEL Corporation – Digital Temperature Sensor with Nonvolatile Registers

operation. When the AT30TS750A receives the NACK, it will release the SDA line so that the Master can send a Stop or
repeated Start condition. If the Master does not send a NACK but instead sends an ACK after the lower byte of the
register has been clocked out, then the device will repeat the sequence by outputting the data again starting with the
upper byte of the register.
After the device powers up or resets, both the T_LOW and T_HIGH Limit Register values will be copied from the Nonvolatile
T_LOW and T_HIGH Limit Registers; therefore, the T_LOW and T_HIGH Limit Register values will default to whatever value was
previously stored in the Nonvolatile T_LOW and T_HIGH Limit Registers prior to power-down or reset. The value of the high
temperature limit stored in the T_HIGH Limit Register must be greater than the value of the low temperature limit stored in
the T_LOW Limit Register in order for the ALERT function to work properly; otherwise, the ALERT pin will output erroneous
results and will falsely signal temperature alarms. In addition, changing either value of the T_HIGH or T_LOW Limit Register
will cause the internal fault counter to reset back to zero.
Figure 6-8. Write to T_LOW or T_HIGH Limit Register
SCK
SDA
Start
by
Master
12 3 4 567 89 12 345 67 89
Address Byte
Pointer Register Byte
1 0 0 1 A A A 0 0 0 0 0 0 0 0 P1 P0 0
MSB
MSB
ACK
from
Slave
ACK
from
Slave
12 3 4 567 89 12 345 67 89
T_LOW or T_HIGH Limit Register
Upper Byte
T_LOW or T_HIGH Limit Register
Lower Byte
D15 D14 D13 D12 D11 D10 D9 D8 0 D7 D6 D5 D4 D3 D2 D1 D0 0
MSB
MSB
ACK
from
Slave
ACK
from
Slave
Stop
by
Master
Figure 6-9. Read from T_LOW or T_HIGH Limit Register
SCK
SDA
Start
by
Master
12 3 4 567 89 12 345 67 89 123 45 67 89
Address Byte
T_LOW or T_HIGH Limit Register
Upper Byte
T_LOW or T_HIGH Limit Register
Lower Byte
1 0 0 1 A A A 1 0 D15 D14 D13 D12 D11 D10 D9 D8 0 D7 D6 D5 D4 D3 D2 D1 D0 1
MSB
MSB
MSB
ACK
from
Slave
ACK
from
Master
NACK
from
Master
Stop
by
Master
Note:
Assumes the Pointer Register was previously set to point to the T_LOW or T_HIGH Limit Register.
AT30TS750A [DATASHEET] 27
Atmel-8855F-DTS-AT30TS750A-Datasheet_102014