ADT7420UCPZ-R2 datasheet(20/24 Pages) AD

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ADT7420

Data Sheet

Rev. 0 | Page 20 of 24

RESET

To reset the ADT7420 without having to reset the entire I2C 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) I2C 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 I2C 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 I2C bus commands (do not acknowledge) while the

default values upload for approximately 200 µs.

The ADT7420 does not acknowledge any other general call

commands.

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