Datasheet

ADT7420 Data Sheet
Rev. 0 | Page 20 of 24
RESET
To reset the ADT7420 without having to reset the entire I
2
C bus,
an explicit reset command is provided. This uses a particular
address pointer word as a command word to reset the part and
upload all default settings. The ADT7420 does not respond to
(does not acknowledge) I
2
C bus commands while the default
values upload for approximately 200 µs. Use the following
sequence to perform a reset:
1. Write to the ADT7420 using the appropriate address.
2. Get acknowledge.
3. Set the register address to 0x2F.
4. Get acknowledge.
5. Apply stop condition.
6. Wait 200 µs for the part to reset its registers to the default
power-up settings.
GENERAL CALL
When a master issues a slave address consisting of seven 0s with
the eighth bit (R/
W
bit) set to 0, this is known as the general call
address. The general call address is for addressing every device
connected to the I
2
C bus. The ADT7420 acknowledges this
address and reads in the following data byte.
If the second byte is 0x06, the ADT7420 is reset, completely
uploading all default values. The ADT7420 does not respond
to the I
2
C bus commands (do not acknowledge) while the
default values upload for approximately 200 µs.
The ADT7420 does not acknowledge any other general call
commands.